[asterisk-dev] pjsip / asterisk 14+: Sometimes outbound calls are forbidden by provider

[Michael Maier]

Hello!

some people are facing a problem regarding forbidden outbound calls to the ISP. They start an outbound call, which is rejected by the
provider. Debugging revealed the reason: The IP used for the outbound INVITE is different from the IP used for the REGISTER. That's why the
ISP forbids the outbound call.



Background:

A SRV lookup gives 3 hosts each with different priority. At the start time, Asterisk takes the IP with the highest priority for the
REGISTER. REGISTER timeout is 660s.

Some time later, lets say 300s, an outbound call is started, which is rejected by ISP (forbidden), because of wrong destination (REGISTER IP
!= INVITE IP).

My question:
Is it possible, that asterisk performs a DNS lookup before it sends the INVITE to the ISP for the outgoing call? At this moment, the DNS
reports changed priorities or the REGISTERed IP isn't there at all any more and therefore, Asterisk uses another IP for the outgoing INVITE?


Thanks,
Michael