[AG-TECH] vic fact

S.Booth spb at epcc.ed.ac.uk
Tue Nov 18 03:35:18 CST 2003


On Mon, 17 Nov 2003, Robert Olson wrote:

> 
> >
> >Can somebody verify that the network admin was right?  If I got the wrong
> >information, please help correcting it.
> 
> What is happening is that rat uses the same port number for the source port 
> and destination port, but vic uses a randomly-assigned port number for its 
> source port.
> 
> I've poked a little about changing this behavior in vic, but the 
> straightfoward fixes I've tried haven't changed it; looks like it'll be 
> more important as time goes on to get this taken care of - after SC perhaps 
> I'll try to take another stab at it.
> 

I went through somehing similar with quickbridge. 
You can work around the problem by both connecting to a quickbridge as the
recent versions use the same port for sending/receiving unicast packets. 

One thing to watch out for with firewall configurations like this is that
they are assuming a
request/response so if they pass a udp packet in the outward direction
they will accept incoming packets from the destination host/port for a
short window afterwards. With RTP data this will only work while all
parties are transmitting. If one party stops transmitting then a short
time afterwards the firewall will start blocking the icoming data
port. The control port will remain open so you will continue to see the
participants in the status window.

 			Stephen
======================================================================
|epcc| Dr Stephen P Booth             Project Manager           |epcc|
|epcc| s.booth at epcc.ed.ac.uk          Phone 0131 650 5746       |epcc|
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