Published: Oct 18, 2019 by

I recently setup a VPN for my home network. To make use of it from remote networks I need to be able to resolve the public IP of my router. Instead of hard coding the IP I setup an domain with Gandi and created an A Record that I update from my router.

Fetching and reporting your IP

This part was fairly easy. With a quick search I found that somebody else had already solved the problem of reporting the public IP from an Ubiquiti router to Gandi! Checkout their work here. Their README provides a nice easy walk through of the setup.

Scheduling it

With the above script updated and working on my router the next thing to do was schedule it.

Quick note only specific directories persist between firmware updates on the EdgeRouter. Because of this I suggest putting the script above in config/scripts/ or config/user-data.The EdgeRouter OS provides a helper utility called task-scheduler which wraps cron. The benefit of task-schedule is that is saves our commands to config so they persist through upgrades. ssh into your router:

ssh <user>@<router>  
configure  
set system task-scheduler task ddnsupdate  
set system task-scheduler task ddnsupdate crontab-spec '0 5 * * 0'  
set system task-scheduler task ddnsupdate executable path '/config/user-data/'  
commit  
save  
cat /etc/cron.d/vyatta-crontab