From: gah@ugcs.caltech.edu   
      
   Mark  wrote:   
      
   > Does SIP v2.0 permit to have the protocol running over non-standard ports   
   > (not 5060)? I've checked through the specification, but wasn't able to find   
   > an answer. It looks like a port can be negotiated and determined during a   
   > registration phase, but I could not confirm this with RFC.   
      
   As a general rule, both TCP and UDP should be able to run over any   
   port that the server recognizes. If you can only configure on end,   
   then you are stuck.   
      
   Some VoIP providers will open many UDP ports to accept incoming SIP   
   connections, others only one. As well as I understand it, the port   
   that RTP runs on is configured through SIP.   
      
   If you are configuring a SIP server, you can select (almost)   
   any port you want.   
      
   > I would appreciate if anyone could help me with this. Thanks !   
      
   I believe both SIP and RTP run over UDP, which tends to be much   
   more flexible with its ports.   
      
   A TCP connection is identified by the quad: source address, source   
   port, destination address, destination port. If replies come back   
   with one of those changed, it won't be recognized. Consider what   
   happens when two people make telnet (or any TCP protocol) connections   
   from the same host to the same server.   
      
   Most often, though, UDP only requires the destination (of replies) to   
   match. When a UDP request is received by a server, replies are sent to   
   the source address and source port of the request. Most clients will   
   recognize the replies, even if they come from (have a source address   
   or source port) different from the one they sent out.   
      
   Among others, that means that multiple SIP connections from the same   
   host (many boxes support two) should have a different port.   
      
   -- glen   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)