Iptables and DNAT (port forwarding)

[Steven Hildreth]

Greetings,   I am using Redhat 7.2 (2.4.7-10) with Iptables (1.2.3) and I am attempting to forward my http traffic to an internal web server.   I have successfully setup NAT and MASQUERAD'ing for the internal network, but I am unable to forward any traffic.   Here is the firewall script I am using (it is not complete and cheesy, but I am taking baby steps): -- #!/bin/sh # ## Script to setup the NAT on a IPTables based firewall # modprobe iptable_nat iptables -F iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE echo 1 > /proc/sys/net/ipv4/ip_forward # Optional modules for NAT modprobe ip_nat_ftp modprobe ip_nat_irc --   The command I have been trying to use with forwarding the http traffic to the internal web server is this:  iptables -t nat -A PREROUTING -p tcp --dport 80 -i eth1 -j DNAT --to-destination 10.100.1.250:80   With (as you most likely have guessed) 10.100.1.250 being the IP of my local internal web server, eth0 is internal and eth1 is the external, I am able to ping the web server from the firewall box and view the apache served pages from the firewall, but unable to forward any external traffic.   Thanks for any help or pointers in advance.   Regards, Steven