[reSIProcate] Odd behaviour with via headers

[Daniel Pocock]

I have noticed some odd behaviour with Via headers.

I have recently upgraded one of my applications from version 6044 of 
resiprocate to the latest svn, and this issue became evident.

a) configure SipStack using non-default port: 
sipStack->addTransport(UDP, 5061)

b) reSIProcate is now listening ONLY on port 5061 (not on 5060) - I've 
confirmed this with 'netstat -unl'

c) send a message (e.g. INVITE) using DialogUsageManager::send(msg)

d) the Via header of the message no longer mentions the non-standard 
port - instead, it defaults to blank

I've been able to work around this by setting the port details in the 
UserProfile object for each outgoing session.  However, it is not 
immediately obvious that this is necessary - it took me 15 minutes just 
to work out that the Via header was different.

To cause further confusion, the Contact header is correct, listing port 
5061.  The Via header and Contact header are therefore not consistent 
with each other - is this intentional?