Problem when blocking ranges of ports using ICS

I have a small network with a WIN98SE system with
ICS connected to the "world"
I have no problem mapping special ports to other
systems in my net when my kids wants to host
a game server or something.
The basic functions are running fine.

The problem is when I am trying to block ranges of
ports.
The blocking seems to work erratically, and seems to
depend on the order of rules, the face of the moon
and something more I can't understand.
Are there any known bugs in ICS when using ranges of ports
or the blocking function ??
In what order are the rules evaluated ??
For example, if there is a rule to map a certain port to an
other system, and then a block rule that is
using a range where the mapped port is included,
what rule take precedence ??

Like this:
Map port 12356 to 192.168.0.10
Block ports 12300-12400

It is hard to experiment with this since I
have to reboot at every test.
Using ICSCFG.

regards...

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