[sip-comm] Incorrect SDP?

I tried to call between SIP accounts and it works, but watching the SDP body
with wireshark I found out something strange.

The first negotiated Media Format is the number 97 (a dynamic one), and from


      dynamic payload type assignments the "a=rtpmap:" attribute (see

      Section 6) SHOULD be used to map from an RTP payload type number

      to a media encoding name that identifies the payload format."

But there is no rtpmap. So I think it is not violating the RFC, but not
following the recommendation.

In case of two Sip-Communicator appears that they agree on payload 97
(whatever it is), while other clients probably would fallback on the next

I don't feel comfortable with this uncertainty, though.

By the way I have another problem, probably not related to Sip-Communicator
but someone could help me.

I am working on 3 Ubuntu virtual machines, one with the server, the others
with the clients. When the clients register to the server, instead of
sending REGISTER test@, they do REGISTER
test@server-desktop.local. I think that the client machine resolves the
server ip into its name, and I don't want that.

Do you know how to avoid it?