[Asterisk-Users] Cisco router and "488 Not acceptable here" messages

[James Harper]

Are there any known problems with Cisco routers (Cisco 837) and SIP
sessions? I have been trying to track down a problem for about 3 hours
now and I think the Cisco router is the culprit!!!

I keep getting "488 Not acceptable here" messages, which are apparently
normally the message you get when a common codec can't be found. I'm
also getting "chan_sip.c:3434 process_sdp: Insufficient information for
SDP (m = '', c = '')" messages, which is strange because the m and c
attributes are definitely there.

When I looked closer, they are received on the first INVITE, then
asterisk says 'proxy auth required', but the INVITE packet with the
proxy auth doesn't have the attributes. A tcpdump on the asterisk server
confirms this.

But, when I do a ethereal dump on my PC where I'm running SJphone, the
attributes are there in the packet.

So something is futzing with my packets, and screwing them up. There is
a Cisco router on my end of the link, so I'm suspecting that!

Any suggestions?

Thanks

James