[VoiceOps] Screwy DSL modem NAT troubles

[Carlos Alvarez]

We go through this all the time with Qwest DSL customers.  Unfortunately 
I don't have model numbers for you, we stopped documenting things when 
we noticed that they have all new modems every few months.  However 
we've had success with having the customer call Qwest and tell them they 
want to run VoIP phones, the Qwest reps seem to know that as a trigger 
and send a compatible modem.  I do recall that the best ones are 
Netopia, and we've had good support when we engage them directly via chat.

We also find that modems start going bad slowly after a couple years, 
and VoIP is the first to get impacted, of course.



Matthew S. Crocker wrote:
> Has anyone else noticed that the latest batch of DSL modems have broken NAT when it comes to VoIP?   I'm seeing stable VoIP customer get broken when the DSL modem is swapped out.  The modem NATs the phones to modem IP port 5060.  So, 10 phones behind the router become one phone to the SBC.  A race condition occurs and phones go in and out of service at random.  It looks like the router is trying to do a SIP ALG but very very broken.
>
> Do anyone have a DSL modem/router they use that works well with VoIP?
>


-- 
Carlos Alvarez
TelEvolve
602-889-3003