NAT External IP address that changes if using backup internet

[billsimon]

Redundancy for customer with 2 ISPs

This is a good and straightforward solution with one catch. If you are using FreePBX’s NAT handling (most people do), then FreePBX needs to know about its external IP. If failover is infrequent and not “flappy” then a simple script[1] can periodically check the external IP, check it against what FreePBX knows, and if different, update FreePBX and reload. Any outage time would be reduced to the amount of time between checks (you could put the script in crontab for every minute). Another possibl…