Thanks all (especially Alex), I know now why, and it does seem that the 'NAT' device - in this case a Draytek Vigor ADSL router is rewriteing
the
SIP packet incorrectly. However, if I wanted to be tolerant of this, is there a way to instruct SER to re-evaluate the 'content-length' and rewrite it correctly?
You might be better fixing the Draytech - who knows what information the NAT box is losing. The problem you have here is it's done 3 rewrites (Via, Call-ID, & RTP o=) each adding five characters but only added 10 to Content-Length; I expect you can imagine the piece of C doing this and
that
If it were just for personal use that would be fine, but we have to support a wide range of clients where we don't have control over their hardware. I think we're going to have to 'correct' the Content-Length field - is there any way we can add additional data to the body and force SER to recalculate it that way?
Linus