Need some advice as I’ve only barely used EPM. I have about 20 VVX 500s in a heavily restricted network. Almost no external connections to the internet. Phones are provisioned and working well. Intermittently, we have network outages and completely lose local DNS. I would like to have these phones s…

Are the phones on Chan-Sip or PJSip?

What does that have to do with DNS?

PJSIP although I’m not sure how that would come into play here

Yes. This is about a DNS problem not a channel driver problem.

[image] Losing connection between pbx and phones on the server network when internet goes out? Networking Are you using chan_sip, that’s a well known limitation if you lose DNS.

Yes internal DNS. Not sure if it’s Microsoft AD but I think it could be. Phones are at very remote locations so we would want that remote location to still be able to make ext-ext calls in the event of a DNS outage

Right but the OP is using IPs not FQDNs in the testing.

Is the phone on the same local network? Is it remote? Do you see the attempts hit the PBX?

Same local network. All hosts on the local network have static IPs. When we simulate a DNS outage and reboot the phone, it boots back up, displays a message about date and time out of sync, and never registers to the PBX

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lzcantrell (Luke Cantrell) August 22, 2025, 1:32pm 8