Phones go into "no service" when internet goes down... still?

Recently had a circumstance where both our primary and backup internet connections went down. Shortly thereafter, all of our phones started to display “no service”. In this location our trunks are only about 50% VOIP and the other half are analog, so obviously bad when this happens. Serious sense of Deja-vu from many years past… I recall this was caused by a DNS lookup issue in asterisk going back probably 6 years or more now but I thought certain it would have been addressed by now… apparently not.

I’ve gone back and found a few old articles and some of my own old notes regarding ways to work around this scenario.

Before I go hacking around and re-inventing a square wheel though… what is the current wisdom with regard to working around this issue?

Anyone have any insight into why a bug like this has remained un-addressed for this many years (or has asterisk deemed that its “not-a-bug”)? Is there a clean way a workaround could be rolled into the distro since this potentially affects any user with SIP trunks, but that isn’t usually discovered until the unfortunate day the internet goes away.


If you use chan sip this is not fixed. If you use pjsip it is fixed. You can not mix. It must all be pjsip

If someones has this issue can he use sip for the phones and pjsip for the sip trunk to fix this problem?

Sure - just be cognizant of the port you are using for each. They will happily coexist in the same installation.