diff --git a/vm/archlinux-vm.sh b/vm/archlinux-vm.sh
index 482f09c85..e1ff0eb28 100644
--- a/vm/archlinux-vm.sh
+++ b/vm/archlinux-vm.sh
@@ -310,7 +310,10 @@ function advanced_settings() {
       HN="arch-linux"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo "${VM_NAME,,}" | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -332,27 +335,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$CORE_COUNT" ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$RAM_SIZE" ]; then
-      RAM_SIZE="2048"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="2048"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 2048)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z "$BRG" ]; then
@@ -365,43 +372,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 "$GEN_MAC" --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$MAC1" ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 "$GEN_MAC" --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$VLAN1" ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$MTU1" ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     echo -e "${GATEWAY}${BOLD}${DGN}Start VM when completed: ${BGN}yes${CL}"
diff --git a/vm/debian-13-vm.sh b/vm/debian-13-vm.sh
index 4b52b7d47..2f3522f16 100644
--- a/vm/debian-13-vm.sh
+++ b/vm/debian-13-vm.sh
@@ -325,7 +325,10 @@ function advanced_settings() {
       HN="debian"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo "${VM_NAME,,}" | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -347,27 +350,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$CORE_COUNT" ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$RAM_SIZE" ]; then
-      RAM_SIZE="2048"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="2048"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 2048)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z "$BRG" ]; then
@@ -380,43 +387,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 "$GEN_MAC" --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$MAC1" ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 "$GEN_MAC" --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$VLAN1" ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$MTU1" ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   select_cloud_init
 
diff --git a/vm/debian-vm.sh b/vm/debian-vm.sh
index cff40a43a..b7193f04f 100644
--- a/vm/debian-vm.sh
+++ b/vm/debian-vm.sh
@@ -315,7 +315,10 @@ function advanced_settings() {
       HN="debian"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -337,27 +340,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="2048"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="2048"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 2048)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
@@ -370,43 +377,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "CLOUD-INIT" --yesno "Configure the VM with Cloud-init?" --defaultno 10 58); then
     echo -e "${CLOUD}${BOLD}${DGN}Configure Cloud-init: ${BGN}yes${CL}"
diff --git a/vm/docker-vm.sh b/vm/docker-vm.sh
index 42fb22091..194470a40 100644
--- a/vm/docker-vm.sh
+++ b/vm/docker-vm.sh
@@ -251,7 +251,10 @@ function advanced_settings() {
     if [ -z $VM_NAME ]; then
       HN="docker"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
     fi
     echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
   else
@@ -275,24 +278,32 @@ function advanced_settings() {
   fi
 
   # CPU Cores
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
+    else
+      exit_script
     fi
-    echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
-  else
-    exit_script
-  fi
+  done
 
   # RAM Size
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 4096 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="4096"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 4096 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="4096"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 4096)." 8 58
+    else
+      exit_script
     fi
-    echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
-  else
-    exit_script
-  fi
+  done
 
   # Bridge
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
@@ -305,42 +316,63 @@ function advanced_settings() {
   fi
 
   # MAC Address
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
+      exit_script
     fi
-    echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
-  else
-    exit_script
-  fi
+  done
 
   # VLAN
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan (leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan (leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
+      exit_script
     fi
-    echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
-  else
-    exit_script
-  fi
+  done
 
   # MTU
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
+      exit_script
     fi
-    echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
-  else
-    exit_script
-  fi
+  done
 
   # Start VM
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
diff --git a/vm/haos-vm.sh b/vm/haos-vm.sh
index 832640e0a..af0b0af80 100644
--- a/vm/haos-vm.sh
+++ b/vm/haos-vm.sh
@@ -391,7 +391,10 @@ function advanced_settings() {
       HN="haos${BRANCH}"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -416,27 +419,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="4096"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="4096"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 4096)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
@@ -449,43 +456,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     echo -e "${DGN}Start VM when completed: ${BGN}yes${CL}"
diff --git a/vm/mikrotik-routeros.sh b/vm/mikrotik-routeros.sh
index 4e46f5900..b2ee376cc 100644
--- a/vm/mikrotik-routeros.sh
+++ b/vm/mikrotik-routeros.sh
@@ -377,7 +377,10 @@ function advanced_settings() {
       HN="mikrotik-routeros-chr"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -399,27 +402,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="2048"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="2048"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 2048)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
@@ -432,43 +439,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     echo -e "${GATEWAY}${BOLD}${DGN}Start VM when completed: ${BGN}yes${CL}"
diff --git a/vm/nextcloud-vm.sh b/vm/nextcloud-vm.sh
index 3307cc6b7..6f14cdbcc 100644
--- a/vm/nextcloud-vm.sh
+++ b/vm/nextcloud-vm.sh
@@ -313,7 +313,10 @@ function advanced_settings() {
       HN="nextcloud-vm"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -335,27 +338,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="2048"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="2048"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 2048)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
@@ -368,43 +375,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     echo -e "${GATEWAY}${BOLD}${DGN}Start VM when completed: ${BGN}yes${CL}"
diff --git a/vm/openwrt-vm.sh b/vm/openwrt-vm.sh
index c7e030245..2ad7de968 100644
--- a/vm/openwrt-vm.sh
+++ b/vm/openwrt-vm.sh
@@ -328,30 +328,41 @@ function advanced_settings() {
     if [ -z $VM_NAME ]; then
       HN="openwrt"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
     fi
     echo -e "${DGN}Using Hostname: ${BGN}$HN${CL}"
   else
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 1 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="1"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 1 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="1"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${DGN}Allocated Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 1)." 8 58
+    else
+      exit-script
     fi
-    echo -e "${DGN}Allocated Cores: ${BGN}$CORE_COUNT${CL}"
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 256 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="256"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 256 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="256"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${DGN}Allocated RAM: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 256)." 8 58
+    else
+      exit-script
     fi
-    echo -e "${DGN}Allocated RAM: ${BGN}$RAM_SIZE${CL}"
-  else
-    exit-script
-  fi
+  done
 
   if DISK_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" \
     --inputbox "Set Disk Size in GiB (e.g., 1, 2, 4)" 8 58 "1" \
@@ -422,41 +433,62 @@ function advanced_settings() {
     exit-script
   fi
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a WAN Vlan (leave blank for default)" 8 58 --title "WAN VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a WAN Vlan (leave blank for default)" 8 58 --title "WAN VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${DGN}Using WAN Vlan: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${DGN}Using WAN Vlan: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
+      exit-script
     fi
-    echo -e "${DGN}Using WAN Vlan: ${BGN}$VLAN1${CL}"
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN2=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a LAN Vlan" 8 58 999 --title "LAN VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN2 ]; then
-      VLAN2="Default"
-      LAN_VLAN=""
+  while true; do
+    if VLAN2=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a LAN Vlan" 8 58 999 --title "LAN VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN2" ]; then
+        VLAN2="Default"
+        LAN_VLAN=""
+        echo -e "${DGN}Using LAN Vlan: ${BGN}$VLAN2${CL}"
+        break
+      fi
+      if [[ "$VLAN2" =~ ^[0-9]+$ ]] && [ "$VLAN2" -ge 1 ] && [ "$VLAN2" -le 4094 ]; then
+        LAN_VLAN=",tag=$VLAN2"
+        echo -e "${DGN}Using LAN Vlan: ${BGN}$VLAN2${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      LAN_VLAN=",tag=$VLAN2"
+      exit-script
     fi
-    echo -e "${DGN}Using LAN Vlan: ${BGN}$VLAN2${CL}"
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DGN}Using Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DGN}Using Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
+      exit-script
     fi
-    echo -e "${DGN}Using Interface MTU Size: ${BGN}$MTU1${CL}"
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     START_VM="yes"
diff --git a/vm/opnsense-vm.sh b/vm/opnsense-vm.sh
index 71ec65f41..13f964588 100644
--- a/vm/opnsense-vm.sh
+++ b/vm/opnsense-vm.sh
@@ -421,30 +421,41 @@ function advanced_settings() {
     if [ -z "$VM_NAME" ]; then
       HN="OPNsense"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
     fi
     echo -e "${DGN}Using Hostname: ${BGN}$HN${CL}"
   else
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 4 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z "$CORE_COUNT" ]; then
-      CORE_COUNT="2"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 4 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="4"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${DGN}Allocated Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 4)." 8 58
+    else
+      exit-script
     fi
-    echo -e "${DGN}Allocated Cores: ${BGN}$CORE_COUNT${CL}"
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 8192 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="8192"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 8192 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="8192"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${DGN}Allocated RAM: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 8192)." 8 58
+    else
+      exit-script
     fi
-    echo -e "${DGN}Allocated RAM: ${BGN}$RAM_SIZE${CL}"
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a LAN Bridge" 8 58 vmbr0 --title "LAN BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
diff --git a/vm/owncloud-vm.sh b/vm/owncloud-vm.sh
index d0ebe2115..742bebc79 100644
--- a/vm/owncloud-vm.sh
+++ b/vm/owncloud-vm.sh
@@ -314,7 +314,10 @@ function advanced_settings() {
       HN="owncloud-vm"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -336,27 +339,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="2048"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="2048"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 2048)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
@@ -369,43 +376,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     echo -e "${GATEWAY}${BOLD}${DGN}Start VM when completed: ${BGN}yes${CL}"
diff --git a/vm/pimox-haos-vm.sh b/vm/pimox-haos-vm.sh
index a3bbba24d..71981cfb2 100644
--- a/vm/pimox-haos-vm.sh
+++ b/vm/pimox-haos-vm.sh
@@ -274,26 +274,35 @@ function advanced_settings() {
     echo -e "${DGN}Using Hostname: ${BGN}$HN${CL}"
   else
     if [ $exitstatus = 0 ]; then
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${DGN}Using Hostname: ${BGN}$HN${CL}"
     fi
   fi
-  CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
-  exitstatus=$?
-  if [ -z $CORE_COUNT ]; then
-    CORE_COUNT="2"
-    echo -e "${DGN}Allocated Cores: ${BGN}$CORE_COUNT${CL}"
-  else
-    if [ $exitstatus = 0 ]; then echo -e "${DGN}Allocated Cores: ${BGN}$CORE_COUNT${CL}"; fi
-  fi
-  RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 4096 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
-  exitstatus=$?
-  if [ -z $RAM_SIZE ]; then
-    RAM_SIZE="4096"
-    echo -e "${DGN}Allocated RAM: ${BGN}$RAM_SIZE${CL}"
-  else
-    if [ $exitstatus = 0 ]; then echo -e "${DGN}Allocated RAM: ${BGN}$RAM_SIZE${CL}"; fi
-  fi
+  while true; do
+    CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
+    exitstatus=$?
+    if [ $exitstatus -ne 0 ]; then exit-script; fi
+    if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+    if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+      echo -e "${DGN}Allocated Cores: ${BGN}$CORE_COUNT${CL}"
+      break
+    fi
+    whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
+  done
+  while true; do
+    RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 4096 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
+    exitstatus=$?
+    if [ $exitstatus -ne 0 ]; then exit-script; fi
+    if [ -z "$RAM_SIZE" ]; then RAM_SIZE="4096"; fi
+    if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+      echo -e "${DGN}Allocated RAM: ${BGN}$RAM_SIZE${CL}"
+      break
+    fi
+    whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 4096)." 8 58
+  done
   BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
   exitstatus=$?
   if [ -z $BRG ]; then
@@ -302,39 +311,56 @@ function advanced_settings() {
   else
     if [ $exitstatus = 0 ]; then echo -e "${DGN}Using Bridge: ${BGN}$BRG${CL}"; fi
   fi
-  MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
-  exitstatus=$?
-  if [ -z $MAC1 ]; then
-    MAC="$GEN_MAC"
-    echo -e "${DGN}Using MAC Address: ${BGN}$MAC${CL}"
-  else
-    if [ $exitstatus = 0 ]; then
+  while true; do
+    MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
+    exitstatus=$?
+    if [ $exitstatus -ne 0 ]; then exit-script; fi
+    if [ -z "$MAC1" ]; then
+      MAC="$GEN_MAC"
+      echo -e "${DGN}Using MAC Address: ${BGN}$MAC${CL}"
+      break
+    fi
+    if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
       MAC="$MAC1"
       echo -e "${DGN}Using MAC Address: ${BGN}$MAC1${CL}"
+      break
     fi
-  fi
-  VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
-  exitstatus=$?
-  if [ $exitstatus = 0 ]; then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default" VLAN=""
+    whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
+  done
+  while true; do
+    VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
+    exitstatus=$?
+    if [ $exitstatus -ne 0 ]; then exit-script; fi
+    if [ -z "$VLAN1" ]; then
+      VLAN1="Default"
+      VLAN=""
       echo -e "${DGN}Using Vlan: ${BGN}$VLAN1${CL}"
-    else
+      break
+    fi
+    if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
       VLAN=",tag=$VLAN1"
       echo -e "${DGN}Using Vlan: ${BGN}$VLAN1${CL}"
+      break
     fi
-  fi
-  MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
-  exitstatus=$?
-  if [ $exitstatus = 0 ]; then
-    if [ -z $MTU1 ]; then
-      MTU1="Default" MTU=""
+    whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
+  done
+  while true; do
+    MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3)
+    exitstatus=$?
+    if [ $exitstatus -ne 0 ]; then exit-script; fi
+    if [ -z "$MTU1" ]; then
+      MTU1="Default"
+      MTU=""
       echo -e "${DGN}Using Interface MTU Size: ${BGN}$MTU1${CL}"
-    else
+      break
+    fi
+    if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
       MTU=",mtu=$MTU1"
       echo -e "${DGN}Using Interface MTU Size: ${BGN}$MTU1${CL}"
+      break
     fi
-  fi
+    whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
+  done
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     echo -e "${DGN}Start VM when completed: ${BGN}yes${CL}"
     START_VM="yes"
diff --git a/vm/truenas-vm.sh b/vm/truenas-vm.sh
index 3e7274543..a4447b898 100644
--- a/vm/truenas-vm.sh
+++ b/vm/truenas-vm.sh
@@ -355,7 +355,10 @@ function advanced_settings() {
     if [ -z $VM_NAME ]; then
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -380,27 +383,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 "$CORE_COUNT" --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 "$CORE_COUNT" --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 "$RAM_SIZE" --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="8192"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 "$RAM_SIZE" --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="8192"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 8192)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 "$BRG" --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
@@ -413,43 +420,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --defaultno --title "IMPORT ONBOARD DISKS" --yesno "Would you like to import onboard disks?" 10 58); then
     echo -e "${DISK}${BOLD}${DGN}Import onboard disks: ${BGN}yes${CL}"
diff --git a/vm/ubuntu2204-vm.sh b/vm/ubuntu2204-vm.sh
index 0c281ec7f..b6e637804 100644
--- a/vm/ubuntu2204-vm.sh
+++ b/vm/ubuntu2204-vm.sh
@@ -310,7 +310,10 @@ function advanced_settings() {
       HN="ubuntu"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -332,27 +335,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="2048"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="2048"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 2048)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
@@ -365,43 +372,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     echo -e "${GATEWAY}${BOLD}${DGN}Start VM when completed: ${BGN}yes${CL}"
diff --git a/vm/ubuntu2404-vm.sh b/vm/ubuntu2404-vm.sh
index eba9846a5..911644550 100644
--- a/vm/ubuntu2404-vm.sh
+++ b/vm/ubuntu2404-vm.sh
@@ -313,7 +313,10 @@ function advanced_settings() {
       HN="ubuntu"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -335,27 +338,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="2048"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="2048"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 2048)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
@@ -368,43 +375,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     echo -e "${GATEWAY}${BOLD}${DGN}Start VM when completed: ${BGN}yes${CL}"
diff --git a/vm/ubuntu2504-vm.sh b/vm/ubuntu2504-vm.sh
index f9040855d..e448a1e0f 100644
--- a/vm/ubuntu2504-vm.sh
+++ b/vm/ubuntu2504-vm.sh
@@ -312,7 +312,10 @@ function advanced_settings() {
       HN="ubuntu"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -334,27 +337,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="2048"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="2048"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 2048)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
@@ -367,43 +374,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     echo -e "${GATEWAY}${BOLD}${DGN}Start VM when completed: ${BGN}yes${CL}"
diff --git a/vm/umbrel-os-vm.sh b/vm/umbrel-os-vm.sh
index fc193d0bb..dc4cb13fb 100644
--- a/vm/umbrel-os-vm.sh
+++ b/vm/umbrel-os-vm.sh
@@ -373,7 +373,10 @@ function advanced_settings() {
       HN="umbrelos"
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     else
-      HN=$(echo ${VM_NAME,,} | tr -d ' ')
+      HN=$(echo "${VM_NAME,,}" | tr -cs 'a-z0-9-' '-' | sed 's/^-//;s/-$//')
+      if [ "$HN" != "${VM_NAME,,}" ]; then
+        whiptail --backtitle "Proxmox VE Helper Scripts" --title "HOSTNAME ADJUSTED" --msgbox "Invalid characters detected. Hostname has been adjusted to:\n\n  $HN" 10 58
+      fi
       echo -e "${HOSTNAME}${BOLD}${DGN}Hostname: ${BGN}$HN${CL}"
     fi
   else
@@ -398,27 +401,31 @@ function advanced_settings() {
     exit-script
   fi
 
-  if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $CORE_COUNT ]; then
-      CORE_COUNT="2"
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+  while true; do
+    if CORE_COUNT=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate CPU Cores" 8 58 2 --title "CORE COUNT" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$CORE_COUNT" ]; then CORE_COUNT="2"; fi
+      if [[ "$CORE_COUNT" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "CPU Cores must be a positive integer (e.g., 2)." 8 58
     else
-      echo -e "${CPUCORE}${BOLD}${DGN}CPU Cores: ${BGN}$CORE_COUNT${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $RAM_SIZE ]; then
-      RAM_SIZE="2048"
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+  while true; do
+    if RAM_SIZE=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Allocate RAM in MiB" 8 58 2048 --title "RAM" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$RAM_SIZE" ]; then RAM_SIZE="2048"; fi
+      if [[ "$RAM_SIZE" =~ ^[1-9][0-9]*$ ]]; then
+        echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "RAM Size must be a positive integer in MiB (e.g., 2048)." 8 58
     else
-      echo -e "${RAMSIZE}${BOLD}${DGN}RAM Size: ${BGN}$RAM_SIZE${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if BRG=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Bridge" 8 58 vmbr0 --title "BRIDGE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
     if [ -z $BRG ]; then
@@ -431,43 +438,61 @@ function advanced_settings() {
     exit-script
   fi
 
-  if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MAC1 ]; then
-      MAC="$GEN_MAC"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+  while true; do
+    if MAC1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a MAC Address" 8 58 $GEN_MAC --title "MAC ADDRESS" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MAC1" ]; then
+        MAC="$GEN_MAC"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC${CL}"
+        break
+      fi
+      if [[ "$MAC1" =~ ^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$ ]]; then
+        MAC="$MAC1"
+        echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "Invalid MAC address format. Use XX:XX:XX:XX:XX:XX (e.g., AA:BB:CC:DD:EE:FF)." 8 58
     else
-      MAC="$MAC1"
-      echo -e "${MACADDRESS}${BOLD}${DGN}MAC Address: ${BGN}$MAC1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $VLAN1 ]; then
-      VLAN1="Default"
-      VLAN=""
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+  while true; do
+    if VLAN1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set a Vlan(leave blank for default)" 8 58 --title "VLAN" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$VLAN1" ]; then
+        VLAN1="Default"
+        VLAN=""
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      if [[ "$VLAN1" =~ ^[0-9]+$ ]] && [ "$VLAN1" -ge 1 ] && [ "$VLAN1" -le 4094 ]; then
+        VLAN=",tag=$VLAN1"
+        echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "VLAN must be a number between 1 and 4094, or leave blank for default." 8 58
     else
-      VLAN=",tag=$VLAN1"
-      echo -e "${VLANTAG}${BOLD}${DGN}VLAN: ${BGN}$VLAN1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
-  if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
-    if [ -z $MTU1 ]; then
-      MTU1="Default"
-      MTU=""
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+  while true; do
+    if MTU1=$(whiptail --backtitle "Proxmox VE Helper Scripts" --inputbox "Set Interface MTU Size (leave blank for default)" 8 58 --title "MTU SIZE" --cancel-button Exit-Script 3>&1 1>&2 2>&3); then
+      if [ -z "$MTU1" ]; then
+        MTU1="Default"
+        MTU=""
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      if [[ "$MTU1" =~ ^[0-9]+$ ]] && [ "$MTU1" -ge 576 ] && [ "$MTU1" -le 65520 ]; then
+        MTU=",mtu=$MTU1"
+        echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+        break
+      fi
+      whiptail --backtitle "Proxmox VE Helper Scripts" --title "INVALID INPUT" --msgbox "MTU Size must be a number between 576 and 65520, or leave blank for default." 8 58
     else
-      MTU=",mtu=$MTU1"
-      echo -e "${DEFAULT}${BOLD}${DGN}Interface MTU Size: ${BGN}$MTU1${CL}"
+      exit-script
     fi
-  else
-    exit-script
-  fi
+  done
 
   if (whiptail --backtitle "Proxmox VE Helper Scripts" --title "START VIRTUAL MACHINE" --yesno "Start VM when completed?" 10 58); then
     echo -e "${GATEWAY}${BOLD}${DGN}Start VM when completed: ${BGN}yes${CL}"