DDNS terminates at update time

Installing and Using OpenWrt Network and Wireless Configuration
1

I've had DDNS running for some time updated by my PiHole, however, I want to set up a new one for my mother on an OpenWrt router (old TPLink) I plan to give to her when I visit next month. To make sure I knew what I was doing I have tried to set this up on my current router a Pi running OpenWrt. This runs fine on first setting and I checking the log get the response from the provider, however, when the next check rolls around there's a time out

091500  WARN : Get registered/public IP for 'mydomain.freeddns.org' failed after 5 retries - TERMINATE
091500  WARN : PID '12873' exit WITH ERROR '1' at 2022-03-16 09:15

There's a whole load of prior errors about missing libraries I think to do with no IPV6 as they are there when it works at first run.

my config


config service 'dynu'
        option enabled '1'
        option lookup_host 'mydomain.freeddns.org'
        option use_ipv6 '0'
        option service_name 'dynu.com'
        option domain 'mydomain.freeddns.org'
        option username 'myname'
        option password 'mypassword'
        option use_syslog '2'
        option check_unit 'minutes'
        option force_unit 'minutes'
        option retry_unit 'seconds'
        option ip_source 'network'
        option ip_network 'Wan'
        option interface 'Wan'
        option check_interval '15'
        option retry_count '5'
        option retry_interval '60'
        option force_interval '720'
        option use_https '1'
        option cacert 'IGNORE'
        option force_ipversion '1'

If I check with ifconfig my pppoe-Wan has the correct external IP address and I can successfully update one of my other dynamic addresses with a script on my PiHole and it does update fine on first run.

2

You can see the detailed logs, at "/var/log/ddns/".

Also, try to execute "nslookup mydomain.freedns.org", and see what happens.

3 
root@Pi-Router:~# nslookup mydomain.freeddns.org
Server:		192.168.70.250
Address:	192.168.70.250#53

Name:      mydomain.freeddns.org
Address 1: 2xx.1xx.2xx.1xx
*** Can't find WDR.freeddns.org: No answer

Returns the IPV4 address correctly, there is no IPV6, ergo the result is similar to other domains I am updating from the PiHole.

The log at /var/log/ddns is the same as the one seen via the log view in luci. This works on first run, I see the response from Dynu in the log of nochg it is only subsequent checks that fail reading the Wan IP.

4

Although the internal script sees to bin out on check I've written a somewhat crude script which at least on my Pi is running.

hostname="mydomain.freeddns.org"
password="mypassword"

# functions
get_wan () {
ifconfig | grep -A 1 "Wan" | grep inet | awk -v OFS="\n" '{ print $2, $NF }' | grep "addr" | grep -oE "\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b"
}
get_host () {
nslookup "$hostname" | grep "Address 1"  | grep -oE "\b((25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b"
}

echo url="https://api.dynu.com/nic/update?hostname=$hostname&password=$password" | curl -k -o -K - 
sleep 60

while :
do
WAN_IP=$(get_wan)
HOST_IP=$(get_host)
if [[  "$WAN_IP" -ne "$HOST_IP" ]]
                then
                echo addresses do not match"
                echo url="https://api.dynu.com/nic/update?hostname=$hostname&password=$password" | curl -k -o -K -
                else
                echo addresses match"
                fi
sleep 900
done

I've put in somewhat more error checks and it resets at midnight and restarts but that's the gist of it.