I tried several times to get ipmasqadm to work correctly and it never did.
My best suggestion would be to upgrade from the 2.2.x kernel you're on now
to 2.4.x and install iptables. The syntax is similar to ipchains, and its
the way things are going (ie ipchains will be obsolete soon).

once you upgraded you're need to run the following:

iptables -A PREROUTING -t nat -p tcp -d 192.168.1.105 --dport 110 -j DNAT
--to 203.101.33.9
iptables -A PREROUTING -t nat -p udp -d 192.168.1.105 --dport 110 -j DNAT
--to 203.101.33.9

(I'm not sure if POP uses UDP, but just to be safe, you might want to add
it as a rule).

That would do it for ya.

ftp://ftp.us.kernel.org for 2.4.3 kernel
http://netfilter.samba.org for the latest and greatest iptables 1.2.1a

BTW: The telnet session should work as a test, regardless if the MAC
actually has a telnet server running (as a previous message stated). You
can talk directly to any port using telnet to see if its there.

Later,
Aton



Message: 1 
Date: Tue, 3 Apr 2001 18:29:54 -0700 (PDT) 
From: A J <incsdirect at yahoo.com> 
To: tclug-list at mn-linux.org 
Subject: [TCLUG] RE: PORT FORWARING 
Reply-To: tclug-list at mn-linux.org
--0-1957747793-986347794=:39004 
Content-Type: text/plain; charset=us-ascii

Hi there,
I'm trying to get the LAN reading the POP mail from an external machine via
port forwarding, but have no luck so far.
My Linux RHL7 has 2 network adapters 203.101.33.177 (eth1) extrenal and
192.168.1.105 (eth0) internal
Users on LAN have their workstations on 192.168.1.* network number. 
The POP server itselft where users have their acounts gets all mail
downloaded to it is on MAC and is on 203.101.33.9
All I need is to make users from 192.168.1.* to connect to 192.168.1.105
(Linux box internal address) and then to make linux to forward connection
to 203.101.33.9 (Mac POP Server) so it's some sort of proxy.
I have tried this on Linux BOX
ipmasqadm portfw -a -P tcp -L 192.168.1.105 110 -R 203.101.33.9 110
then I to telnet from my LAN
telnet 192.168.0.105 110 
and I expect to have response from MAC POP server
But it says 'Unable to connect to host"
What am I doing wrong? Is there any other solutions to this?
Thank you very much in advance
Arthur