Losing connection between pbx and phones on the server network when internet goes out?

Hello, I been having problems with my freepbx working when the internet goes out. When my internet goes out I lose the conenction from the freepbx server and my phones. They are all on the same network and I can still access the freepbx internally but the phones say they can not access the freepbx. My phone lines are analog. I have a pcie analog card on the freepbx server. But I’m unsure why I’m losing the connection from the server to the phones?

When I go to the phones they say there not registering. I have Cisco9971 phones. It was helped from the community years ago. I’m kind of rusty trying to figure this out. The freepbx is on the same network as my phones all use a 10.1 address.

So my question is why is it losing connection and the phones won’t register on the server when both are on the same network and I can reach the server with no problem with or without internet connection?


You would need to provide logs (including from the phone, if nothing is showing on the Asterisk logs), but my guess would be that DNS is timing out on them. This could include reverse lookups for a domain you don’t master locally, which would otherwise receive a quick not found response.

Are you using chan_sip, that’s a well known limitation if you lose DNS.

Yes I’m using chan Sip. Back then I thought that is what I was suppose to use. that was back in 2015. I’m looking into building a new freepbx but it has been over 7 years sense I put this in.


Hello lgaetz, What Can I use besides Chan_sip to still use the freepbx to still make calls if the internet does go out?


The currently supported SIP channel driver, chan_pjsip, supposedly tolerates DNS outages better. chan_sip is no longer supported.

Alternatively, configure local DNS servers, to cover all the addresses and domains within your intranet…

hello david55, Thank you. You know what I didn’t realize My dns servers are setup for and,I didn’t realize about that part. and I will change it to the chan_pjsip. Thank you


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