QuteCom uses src-port 5060 for outgoing connections. why?

[Chris Maciejewski]

My understanding of RFC 3261 is that Qutecom (or any other SIP
(soft)phone - User Agent) is in fact both User Agent Client and User
Agent Server. See RFC 3261 - page 25:

"User Agent (UA): A logical entity that can act as both a user
         agent client and user agent server."

It acts as UAC when sending "INVITE" to make "outbound" call, but acts
as UAS when replying to "inbound" INVITE from proxy/other UAC.

Also it is perfectly valid to make SIP "calls" directly between User
Agents - not via any proxy (registrar) (so called "IP calling"), and
that is why UAS part of any SIP phone should listen on well known port
5060.

Regard,
Chris


2008/8/11 Klaus Darilion <klaus.mailinglists at pernau.at>:
> IMO every SIP client (not servers) should use a random port as default. This
> is also a security feature - nobody except the registrar need to know the
> port used by the SIP client.
>
> Nevertheless, having an "advanced option" to configure a static port may be
> useful, e.g. for testing purposes.
>
> regards
> klaus