[Asterisk-Users] How to best debug SIP registration failure

[Philipp von Klitzing]

Hi!

> I am having trouble getting SIP phones to register with Asterisk. I know
> that the phone can register with FWD and I have used tcpdump to see the
> registration packets arrive at the Asterisk server, but nothing goes back.

Sounds like your SIP client is behind NAT and you need nat=yes in 
sip.conf, and/or you need to enable STUN support in your SIP client so 
that the correct sender IP address.

Note that SIP clients can only register with Asterisk if you have set 
host=dynamic and you have type=friend or type=peer set.

> How should I attack the problem?

First collect and provide meaningful information incl. sip.conf

1. Is NAT between the SIP phone and Asterisk? Does your SIP client use 
STUN? Which SIP client do you use?
2. Is Asterisk itself behind NAT? If yes first try to run Asterisk 
without NAT.
3. Does it work if you use a IAX client instead of a SIP client?

> What debugging tools exist to try to determine why Asterisk is not
> accepting the registration requests?

- at the CLI enter SIP DEBUG (and SIP NO DEBUG when done)
- press F9 if your client is X-Lite
- you can use ethereal for more details, however usually the above two 
tools should already be sufficient

Philipp