i have a server running redhat 7.1 up and running, and i am able to download things to my PC workstation just fine, but if i try to download something to my mac in IE i get a "PORT argument must be greater than 1025" error, i think its because the ftp link i am clicking on is seeing the 192.168.0.2 address rather than the real internet address of my server. i am using ipchains and this is all i have in it:
ipchains -P input ACCEPT
ipchains -P output ACCEPT
ipchains -P forward ACCEPT
ipchains -A forward -i ppp0 -j MASQ

what am i missing?

Try to make a file called /etc/rc.d/init.d/firewall with following:

#!/bin/sh
inside=192.168.0.0/24
outside=outside_ip_here
anywhere="0.0.0.0/0"

OUTSIDE_IFACE=ppp0
INSIDE_IFACE=eth0

test -x /sbin/ipchains || exit 0

case "$1" in
start)
echo "Starting the firewall"

`echo 1 > /proc/sys/net/ipv4/ip_forward`
MOD="-A"

;;
stop)
echo "Stopping the firewall"

MOD="-D"

;;

*)
echo "Ussage: firewall start or firewall stop"
exit 1

esac

ipchains $MOD forward -s $inside -d ! $inside -j MASQ

ipchains $MOD input -j ACCEPT -i $OUTSIDE_IFACE -p TCP -s $inside ftp

ipchains $MOD input -j ACCEPT -i $OUTSIDE_IFACE -p TCP -s $inside ftp-data

ipchains $MOD input -j ACCEPT -i $OUTSIDE_IFACE -p ICMP -d $outside

ipchains $MOD input -j ACCEPT -i $INSIDE_IFACE -p ICMP -d $outside

ipchains $MOD input -j DENY -i $OUTSIDE_IFACE

ipchains $MOD output -p tcp -s $inside -d $anywhere ftp -t 0x01 0x10

ipchains $MOD output -p tcp -s $inside -d $anywhere ftp-data -t 0x01 0x08

ipchains $MOD output -p udp -s $inside -d $anywhere snmp -t 0x01 0x04

ipchains-save

CAUTION: ipchains and $inside or $ outside to be on the same line here I can't write on the same line. Every command ipchains on one line in that /etc/rc.d/init.d/firewall file .
The same problem with ipchains and 0x10 and others. I put a space between every line. Give execution permissions to that firewall file and then run it with root login.

Regards.

Oh, it looks good.
Put that line in your file without CAUTION.

Be CAREFUL with that execution permision of firewall.
Run it and all will be ok , I think .

Regards.