[Astlinux-users] Network connectivity and DNS issues

[Michael K. <mic...@ip...>]

Hi Group

I have started a new thread although this is a continuation of my intermittent issues with sip trunks not coming back after a network outage.
After some testing in the lab I have realised that most of these problems are related to DNS resolution.

Basically I am using sip domain names for all my providers so DNS resolution is necessary. What I have found is that if for some reason DNS resolution is not possible (e.g. network is down), if the system is rebooted or Asterisk loses the resolved address, it no longer sends the OPTIONS pings as it cant find the address obviously.
Yes that makes sense however the problem arises when the network is restored, Asterisk is completely unaware and therefore makes no attempt in resolving the address.
I believe this is what is causing my intermittent issues which is easily resolved by doing an Asterisk Reload when network connectivity is restored. I have also enabled the Asterisk dnsmgr which does not fix the problem. I suspect that if it couldn't initially resolve it then it gives up totally.

So what is the fix. Here are some of my options:

  1.  Don't use DNS but just use the IP Address instead. This will most certainly resolve the issue but is it the best way? Something in the Hosts file maybe?
  2.  Perform sip monitoring using the SIP Monitor script or Monit. If the SIP URL is resolvable but the status is UNKNOWN then issue a module reload of chan_sip
  3.  Something else

PS the SIP Monitor does not seem to work for me. It only sends me an email when the system is rebooted.
Thanks all.

Regards
Michael Knill