PlusTalk (SIP VoIP) registration error

[Tim]

I wonder whether the work firewall (a CISCO PIX) is doing in-packet
processing for SIP; I know I've had to disable the SIP alg on my home
router/firewall.

The cisco probably has its SIP ALG switched on, and they usually work.


The ALG's in lots of home routers do more harm than good.


Do plusnet have an outbound proxy that they suggest you use?


The error message looks like it has come from SER, so looks like they
haven't installed the nathelper parts of SER.

Tim

[Chris Davies]

Post by Tim
The cisco probably has its SIP ALG switched on, and they usually work.

Yeah, looks plausible, thanks.

Post by Tim
The ALG's in lots of home routers do more harm than good.

Agreed. Most definitely!

Post by Tim
Do plusnet have an outbound proxy that they suggest you use?

sip.plus.net, but it's still objecting even when I use that.

Post by Tim
The error message looks like it has come from SER, so looks like they
haven't installed the nathelper parts of SER.

SER as in http://www.iptel.org/ser/ ?

Interestingly I hard-coded my home (static) IP address in the SIP
application, and now it works fine not only at home - reasonably enough -
but also at work (i.e. the CISCO PIX appears to be handling the clearly
wrong IP address "correctly")

I'd also tried using a STUN server, but at home the service complained
I had a Symmetric NAT and so STUN couldn't help me. (I thought Symmetric
NAT was the "most correct" implementation of NAT? In which case it's
amazing that STUN can even work at all...?)

Chris