UDP, ICS and Kerio FW question

I have a LAN with 3 PCs.
PC1 is Win98Se with ICS and Kerio FW 2.1.5 and DSL.
"Running on internet gateway" is checked in Kerio.
No special setups are made for ICS.

PC2 can play Counter-Strike without any special rules in Kerio.
My problem is that we (well..my sons..) can't play from PC3 without
a special rule to permit input UDP from the Counter-Strike server.
They are connected to the same server, but not at the same time.
The setup for PC2 and PC3 are identical as far as I can see.
I assume that Kerio "understands" that when an UDP block
is sent from a local port to "wan" it should permit the returning
UDP blocks from "wan" back to the sending port.

Or at least I assume that's how it works from PC2 or ?????
(how could it work otherwise ??)

Why doesn't this work from PC3 ??

Or is my understanding of how Kerio/ICS handles UDP wrong ??

And how does ICS handles UDP. I can't find very much info
about WIN98SE-ICS at all. For example it seems like it
treats ports below 1024 differently from ports above 1024.
Is there any in-dept info about WIN98SE-ICS available ??
(btw using icsconfig)

Any suggestions....

john rehn
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