IPSEC Filter

From: Robin Twiggs (rstwiggs@lantic.net)
Date: 12/31/02 

From: "Robin Twiggs" <rstwiggs@lantic.net>
Date: Tue, 31 Dec 2002 05:32:23 +0200

I am trying to apply an IPSEC filter to limit incoming FTP to a specific IP
Subnet.
The incoming IP is dynamic and can be anything between 203.45.170.0 and
203.45.240.255

When I try to enter the filter as
IP 203.45.0.0
Subnet 255.255.0.0
I get a message that this setting is invalid.

Am I missing something here?

Thanks in advance.
Robin