My recent experience with Comcast Business is that it does not permit
fixed-IPs with either bridged mode or customer modems.
Also they have a 'feature' called SecurityEdge which is now on by
default (didn't used to be). It blocks all sorts of things but
currently it is possible to go to the account website and turn it back
off. It's pretty evil for anyone that wants to, e.g., run a DNS server
(evil = not possible due to a number of things including caching things
it shouldn't etc.). I don't know about SIP as I have not attempted to
run SIP over that particular connection, but I wonder if it might interfere.
On 9/11/2024 16:06, Tim Burke wrote:
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.
