nat

This tutorial shows how to set up a Ubuntu 6.10 server (Edgy Eft) as a firewall and gateway for small/medium networks. The article covers the installation/configuration of services such as Shorewall, NAT, caching nameserver, DHCP server, VPN server, Webmin, Munin, Apache, Squirrelmail, Postfix, Courier IMAP and POP3, SpamAssassin, ClamAV, and many more.

This tutorial shows how to set up network-address-translation (NAT) on a Linux system with iptables rules so that the system can act as a gateway and provide internet access to multiple hosts on a local network using a single public IP address. This is achieved by rewriting the source and/or destination addresses of IP packets as they pass through the NAT system.