Re: Verizon Wireless LTE/4G and SIP Header Manipulation

[Jared Mauch <jared () puck nether net>]

> On Sep 22, 2015, at 4:24 PM, Christopher Morrow <morrowc.lists () gmail com> wrote:
>
> On Tue, Sep 22, 2015 at 4:16 PM, Mark Stevens <manager () monmouth com> wrote:
> > The TAG unique identifier is being changed and this only happens through VZ
> > LTE networks, not wired networks or even other cellular data networks
> > (Sprint, ATT, T-Mobile)
> > Their phones are IPV6 so the packets are getting converted to IPV4 so it is
> > either happening there or there is a global ALG in Verizon land that is
> > doing it .
> > For positive proof I would need Verizon to fess up (LOL) but that will not
> > happen or sniff traffic from the cellphone itself.
>
> welp, interesting, good luck in your battle with the pstn.

I’ll say it’s not just VZW that does this, there are issues with many CPE devices
that mangle SIP traffic due to broken ALG.  My plea is if you’re a carrier
that provides a CPE, *please* provide an option to disable the ALG, or expose it
to the customer so they can disable it.  *Looks in 7018/7132 direction*

- Jared