Issues with SIP packets between VZ Fios and NTT

Pete Rohrman prohrman at
Mon May 13 17:52:11 UTC 2019

Dovid Bender,

I'm seeing the  same sort of thing.  Polycom phones.   Multiple 
customers getting to me from Verizon in NYC area.  I'm seeing phones 
register for a while, then drop off, then I see them trying to re-reg 
resulting in your 401 below.

Call me.  212 497 8015.  Let's look at this.


Pete Rohrman
Stage2 Support
212 497 8000, Opt. 2

On 5/13/19 12:20 PM, Dovid Bender wrote:
> Thought of that. Customers have their own CPE's. So far the only thing 
> mutual here is that it's NTT -> VZ. Here is what I found so far 
> looking at two Polycom phones using non standard ports (e.g. not 5060)
> 1) PhoneA tries to register multiple extensions and for each request 
> we send a 401. We expect to get back a REGISTER request with a no-once 
> but we don't. This happens for a while and then magically it starts 
> working.
> 2) PhoneB tries to register the time time as PhoneA and has no issues.
> At first I thought it was something possibly with the SIP call-ID but 
> I ruled that out since in the same SIP DIALOG it was not working then 
> it started. Also the seems to be per phone each phone is behind NAT 
> and the traffic is coming from a different NAT'd port. Seems like 
> there is some device in the middle that is randomly dropping traffic 
> on specific sessions.
> On Mon, May 13, 2019 at 11:40 AM Brielle Bruns <bruns at 
> <mailto:bruns at>> wrote:
>     On 5/13/2019 9:21 AM, Dovid Bender wrote:
>     > Hi,
>     >
>     > Over the last 48 hours we have been getting a lot of alerts of
>     customers
>     > phones losing registrations to us. All the complaints are coming
>     from
>     > customers that are on VZ Fios in the NYC area. Anyone else see
>     anything
>     > strange going on?
>     >
>     While you are diagnosing, might check to make sure that the SIP
>     ALG is
>     disabled on all of their routers too.
>     -- 
>     Brielle Bruns
>     The Summit Open Source Development Group
>   /
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