FreeDNS (afraid.org) dynamic DNS updater script: e.g put in /etc/cron.hourly/update-dynamic-dns.sh

update-dynamic-dns.sh

#!/bin/sh
# FreeDNS updater script
# Adapted from https://freedns.afraid.org/scripts/update.sh.txt
# sudo apt install dnsutils wget

DOMAIN="foo.my-custom-domain.com"
API_KEY="put your API key (base64 string) here"
SHOULD_UPDATE=0

# -f is the only argument supported right now (forces update even if address appears correct)
[ "${@:-0}" = "-f" ] && {
  echo "Forcing update"
  SHOULD_UPDATE=1
}

current=$(/sbin/ifconfig eth0 | grep 'inet' | cut -d: -f2 | awk '{ print $2}'|head -n 1)
registered=$(nslookup $DOMAIN|tail -n2|grep A|sed s/[^0-9.]//g)
external=$(wget -q -O - http://checkip.dyndns.org|sed s/[^0-9.]//g)
echo "current = $current, registered = $registered, external = $external"
[ "$current" != "$registered" ] && {
  echo "Current entry does not appear to match"
  SHOULD_UPDATE=1
}

[ "$SHOULD_UPDATE" = "1" ] && {
  echo "Updating now ($(date))"
  #UPDATEURL="http://freedns.afraid.org/dynamic/update.php?$API_KEY" # Use public IP / default
  UPDATEURL="http://freedns.afraid.org/dynamic/update.php?$API_KEY&address=$current" # use address specified in $current
  wget -q -S -O - $UPDATEURL
}

I'll remember to try this once I need DDNS, VPS-es are making me angry I'm probably going to phantom host my stuff from home pretty soon. Cheers!

I'll remember to try this once I need DDNS, VPS-es are making me angry I'm probably going to phantom host my stuff from home pretty soon. Cheers!

Good luck! Note that this uses the older ifconfig method and should probably be updated to use the newer ip addr & friends.

ahh yes, ofc for linux yes. thanks for noting that