Two things that seem to help whenever I'm dealing with bizarre Comcast issues....have her call in and:

* Ask for "Security Edge" to be disabled if it's enabled (last time we did this Comcast told us they couldn't permanently disable it unless we paid a lot more per month for service and it would automatically enable every reboot, but another rep permanently disabled it for us)

* Ask them to disable "Smart Packet Detection" if she's using a router that has that feature

Those two features seem to mess with a lot of traffic--specifically DNS (re-routing any unencrypted DNS request to Comcast's own servers) and SIP.

Of course enabling TLS for your SIP connections would probably help significantly--not just with connectivity, but security.

-A

On Tue, Sep 10, 2024 at 12:20 PM Matt Hoppes <mattlists@rivervalleyinternet.net> wrote:

I have an employee who has recently switched to Xfinity cable service.
Ever since they switched their internet service their work phones will
not stay registered for more than about 3 minutes.

These same phones have been used on many ISPs without issues. The same
config has been used behind multiple levels of NAT without issues.

She was fine, until she switched to XFinity.

Of course, XFinity support is absolutely worthless.

Anyone from XFinity Tier 3 or such that might be able to offer assistance?

I suspect it's something stupid with either NAT overload in the modem or
the modem not keeping the SIP channels open.

I've tried playing around with registration times without any success.
And again, we've never had issues with these phones or this setup with
any other ISP.