fix(vm): validate MTU input - require 576-65520 range, re-ask on invalid

2026-05-15 04:54:58 +02:00 · 2026-03-16 13:52:38 +01:00
parent 39e73d5b20
commit f22ab64170
15 changed files with 237 additions and 145 deletions
--- a/vm/archlinux-vm.sh
+++ b/vm/archlinux-vm.sh
@@ -403,18 +403,24 @@ function advanced_settings() {
    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}"
--- a/vm/debian-13-vm.sh
+++ b/vm/debian-13-vm.sh
@@ -418,18 +418,24 @@ function advanced_settings() {
    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

--- a/vm/debian-vm.sh
+++ b/vm/debian-vm.sh
@@ -408,18 +408,24 @@ function advanced_settings() {
    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}"
--- a/vm/docker-vm.sh
+++ b/vm/docker-vm.sh
@@ -348,17 +348,24 @@ function advanced_settings() {
  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
--- a/vm/haos-vm.sh
+++ b/vm/haos-vm.sh
@@ -487,18 +487,24 @@ function advanced_settings() {
    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}"
--- a/vm/mikrotik-routeros.sh
+++ b/vm/mikrotik-routeros.sh
@@ -470,18 +470,24 @@ function advanced_settings() {
    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}"
--- a/vm/nextcloud-vm.sh
+++ b/vm/nextcloud-vm.sh
@@ -406,18 +406,24 @@ function advanced_settings() {
    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}"
--- a/vm/openwrt-vm.sh
+++ b/vm/openwrt-vm.sh
@@ -471,17 +471,24 @@ function advanced_settings() {
    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"
--- a/vm/owncloud-vm.sh
+++ b/vm/owncloud-vm.sh
@@ -407,18 +407,24 @@ function advanced_settings() {
    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}"
--- a/vm/pimox-haos-vm.sh
+++ b/vm/pimox-haos-vm.sh
@@ -339,17 +339,23 @@ function advanced_settings() {
    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
  done
-  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 $MTU1 ]; then
-      MTU1="Default" MTU=""
+  while true; do
+    MTU1=$(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"
--- a/vm/truenas-vm.sh
+++ b/vm/truenas-vm.sh
@@ -451,18 +451,24 @@ function advanced_settings() {
    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}"
--- a/vm/ubuntu2204-vm.sh
+++ b/vm/ubuntu2204-vm.sh
@@ -403,18 +403,24 @@ function advanced_settings() {
    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}"
--- a/vm/ubuntu2404-vm.sh
+++ b/vm/ubuntu2404-vm.sh
@@ -406,18 +406,24 @@ function advanced_settings() {
    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}"
--- a/vm/ubuntu2504-vm.sh
+++ b/vm/ubuntu2504-vm.sh
@@ -405,18 +405,24 @@ function advanced_settings() {
    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}"
--- a/vm/umbrel-os-vm.sh
+++ b/vm/umbrel-os-vm.sh
@@ -469,18 +469,24 @@ function advanced_settings() {
    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}"