They do not do CGNAT, as far as I know. (Fixed wired broadband should never be behind CGNAT, but that’s a topic for another thread :-) )
Should only apply if you are using Comcast’s CPE for NAT. I had Comcast service some time ago, using their rental CPE in bridged mode, and had no issues with third party SIP. Sent from my iPhone > On Sep 11, 2024, at 17:44, Brandon Ambrose <bpambros...@gmail.com> wrote: > > > Does this apply only to customers using their proprietary gateway or > customers on a CGNAT service with them? > > I have been a Comcast customer for years, with my own equipment, and have > never had issues using Polycom SIP phones on RingCentral. > > This is getting a little concerning for me as we are planning to roll out SIP > phones direct to users at home soon. > > Brandon Ambrose > Network Administrator >> On Sep 11, 2024 at 6:15 PM -0400, Matt Hoppes >> <mattli...@rivervalleyinternet.net>, wrote: >> I have not, but we've run these phones with SIP ALG devices before >> without issue. I'll have them check. >> >>> On 9/10/24 9:17 PM, Tim Burke wrote: >>> Have you tried placing the CPE in “bridged" mode? It’s been a while since >>> I’ve done anything with Comcast CPE, but I remember their CPE doing SIP ALG >>> when acting as a router. >>> >>>> On Sep 10, 2024, at 2:17 PM, Matt Hoppes >>>> <mattli...@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. >>>> >>>> >>>
