I experienced some thing strange this morning related to PJSIP Endpoints not responding to registration attempts. I logged a bug ticket on Git and provided a core dump. The dump provided the following SIP blocking cause by SRV not being available:
The backtrace shows realtime in use for identify sections, and a DNS query blocking for SRV of “_sip._udp.sip.mydomain.local” waiting for a response. This would then block handling of SIP traffic.
Our voice provided had a 6 hours maintenance outage which cause my trunk to them being out of services.
I need assistance related too how I can avoid this from happening again? Any assistance or guidance will be appreciated.
It would prevent SRV lookups, but it wouldn’t stop normal A/AAAA lookups. To stop those you either store IP addresses on the identify section, or you don’t use realtime for identify in which case the resolution would only occur at configuration load time.
I have checked on the DNS servers and I don’t have a SRV record. We only have a A record.
If I disabled SRV lookup will it avoid the SIP blocking from happening in the future if this services provider is offline for long periods of times.
Reason I want to avoid the SIP Blocking is because I have redundancy trunks to other providers.
As a side note: If you’re really using .local for your local domain, you should consider changing this. The .local TLD is reserved for use with mDNS and will be tried to be resolved via mDNS first (making it slow) but also allowing some malicious or misconfigured client to simply hijack DNS names on your network.