UDMP Allow use of AT&T DHCP IP as static IP and keeps the lease alive

07-renew-public-att-dhcp.sh

#!/bin/bash

# testing retry ability - 12/29/2024

# Polls AT&T's DHCP server for updates, to keep static IPs alive.
# This allows UDM Pro users to set their DHCP IP as 'static' in the 'Internet' section
# allowing the use of static IP configuration in Unifi Network.

# Steps:

# 1. Find your IP, netmask (subnet), and gateway. `ifconfig` will list your interfaces.
# eth8 is RJ45, eth9 and eth10 are top and bottom SFP+ respectively (on UDM)

# 2. find your gateway with a subnet calculator. Enter the netmask (subnet) we found with `ifconfig` 
# Your gateway will be the first one in the range listed
# https://www.calculator.net/ip-subnet-calculator.html

# 3. In the UDM's internet settings, change it from DHCPv4 to Static IP, and enter the ip, subnet, and gateway we found and apply
# Your internet should stay up at this point, but will decay. Setting up this script will keep it alive.

# 4. Add your static IP block to the "Additional IP Addresses" section

# 5. ssh into your UDM.

# 6. install the on-boot-script from unifi-utilities: 
# https://github.com/unifi-utilities/unifios-utilities/tree/main/on-boot-script
# (I ran into issues installing this, stating there was no internal storage. However the systemctl "on-boot" was still enabled. It doesn't really matter since the script will still trigger on boot and run our keep alive script, and just exit with a bad code)

# 7. Place this entire script in the directory `/data/on_boot.d/` and name it `07-renew-public-att-dhcp.sh`
# use vi or install nano. If you don't know what either of these are, install nano: `apt-get install nano`
# you can run `nano /data/on_boot.d/07-renew-public-att-dhcp.sh` to edit it

# 7.5. edit the lines below to meet your needs. 

# 8. run `chmod +x /data/on_boot.d/07-renew-public-att-dhcp.sh` to make our new script executable

# 9. add a the included log rotate script to `/etc/logrotate.d/` and name it `udhcpc`
# `nano /etc/logrotate.d/udhcpc`

# 10. kick off our script for the first time by running `/data/on_boot.d/07-renew-public-att-dhcp.sh`
# and check the logs with `cat /var/log/udhcpc.log`

# 11. if everything looks good, reboot your UDM and ssh back into it once booted and check the logs again.
# `cat /var/log/udhcpc.log`

# Credit to https://community.ui.com/questions/Additional-IP-with-DHCP-primary-on-UDM-Pro/ceeaa11b-b1f2-442d-a8ba-6cdfcc29c7f6
# Tested on 4.1.13

PUBLIC_DHCP_IP="" # public ip we got earlier
WAN_PORT="eth10" # see above for likely eths

# both of these are customizable
RETRY_LIMIT=10  # Number of retries
RETRY_INTERVAL=30  # Seconds to wait between retries


# dont touch these
attempt=0
success=false

while [[ $attempt -lt $RETRY_LIMIT && $success == false ]]; do
    nohup /usr/bin/busybox-legacy/udhcpc --foreground --interface $WAN_PORT --script /usr/share/ubios-udapi-server/ubios-udhcpc-script -r $PUBLIC_DHCP_IP >/var/log/udhcpc.log 2>&1 &
    pid=$!
    wait $pid
    exit_status=$?
    if [[ $exit_status -eq 0 ]]; then
        echo "Command executed successfully."
        success=true
    else
        echo "Command failed with status $exit_status. Attempting retry in $RETRY_INTERVAL seconds..."
        sleep $RETRY_INTERVAL
    fi
    ((attempt++))
done

if [[ $success == false ]]; then
    echo "Failed to execute command after $RETRY_LIMIT attempts."
fi

udhcpc

# /etc/logrotate.d/udhcpc
# Rotate the logs to keep them from filling up the system

/var/log/udhcpc.log {
        weekly
        rotate 1
        size 100K
        compress
        delaycompress
}