FIRE|GATE is a Linux IPtables script for use as a firewall and NAT/masquerade router for home networks or SOHO applications. It shares access to a single internet connection from multiple workstations, and can optionally forward all inbound HTTP, SMTP or other requests to internal servers (as opposed to a DMZ).

Hardware requirements are modest, with an i486 with 16MB RAM being capable of handling at least 10 machines (if not many more). Since it makes use of the netfilter code in the 2.4 kernel, FIRE|GATE is more robust and configurable, not to mention considerably shorter, than an equivalent IPchains script.

FIRE|GATE differs from many other examples online as follows:

• Heavily commented, to be as understandable as possible
• Fully contained in one script - compact and manageable
• Includes multiple SYSCTL parameters for increased security
• Attempts to allow IM client file transfers (a rare inclusion)
• Accepts start|stop|restart|status commands from /etc/init.d
• No need to specify or grep the external IP, even if DHCP'd