The current list has 4 IPv4 IP range and upon checking my server firewall(last updated 3 years ago), I can see I have the first 3 entries in there.
So in the last 3 years, Github has added 1 new IP range which is missing from my server but even then, no webhook call has ever failed to my CI server.
As a precaution I just updated my server firewall right now.
You could of course write a cron script to regularly check Github hooks IPs and update firewall if Github changes it's webhooks IPs.
The current list has 4 IPv4 IP range and upon checking my server firewall(last updated 3 years ago), I can see I have the first 3 entries in there.
So in the last 3 years, Github has added 1 new IP range which is missing from my server but even then, no webhook call has ever failed to my CI server.
As a precaution I just updated my server firewall right now.
You could of course write a cron script to regularly check Github hooks IPs and update firewall if Github changes it's webhooks IPs.