[Guy Harris <guy@xxxxxxxxxx>]

> I've linked PC with Ethereal to an hub to sniff UDP packets from a router.These
> UDP packets are generated by a SmartBits 200. No UDP ports are setted (Source
> and Destination Port are 0)on SmartBits 200.
> Two problems:
> 
> 1)Viewing the Ethereal Logs, I see column "Protocol"  PGM (and not UDP)

What are the source *and* destination port numbers of the packets?

If either one is zero, they will be treated as PGM packets, because the
PGM dissector doesn't really allow you to disable PGM dissection - the
PGM-over-UDP encapsulation port number defaults to 0, but it doesn't
treat that as an indication that it shouldn't make any UDP port act as a
PGM port, it treats it as an indication that it should make port 0 be
the port for PGM.

This is arguably a bug.

> In the detail view of the packets I see correctly packets UDP but  Source
> port is setted to 17512(instead of zero).

Well, perhaps the source port of the packet, as it was put onto the
network, *is* 17512, regardless of how the SmartBits 200 is configured. 
What is the destination port?