Firewalls mailing list fuzzy search allows you to search the archive databases for certain topics.

Cryptography, Firewalls, and Computer Security Links compiled by Mark Henderson. Includes links to a large amount of information such as security advisories, underground hackers, firewalls, CGI holes, spook info, and much much more.

Internet Firewalls FAQ, maintained by Marcus Ranum and Matt Curtin, gives a general overview of firewalls and details how to set up and implement various kinds of generic firewalls as well as giving references to other firewall resources.

The Firewall Product Overview lists commercial and public domain firewall vendors, what platforms the firewalls run on, and contact information as well as reseller addresses and other firewall related services and products.

Gauntlet firewall includes a VPN, firewall, and single view rule functionality.

IP Filter is a TCP/IP packet filter, suitable for use in a firewall environment. To use, it can either be used as a loadable kernel module or incorporated into your UNIX kernel; use as a loadable kernel module where possible is highly recommended. Scripts are provided to install and patch system files, as required. Also refer to the small FAQ for common questions.

IPfirewall, available as part of the Juniper Firewall Toolkit, is an IP packet filtering tool. Juniper is a proxy-based firewall designed to work on a dual homed bastion host that does not forward packets between interfaces.

ipacl - sysvr4 streams module that implements packet filtering in the kernel

screend provides a daemon and kernel modifications to allow all packets to be filtered based on source address, destination address, or any other byte or set of bytes in the packet. Should work on most systems that use Berkeley-style networking in the kernel, but requires kernel modifications.

Freestone, and its commercial counterpart Brimstone, are hybrid model firewalls.

drawbridge with des is a copyrighted but freely distributable bridging IP filter with a powerful syntax and good performance. It includes the tools filter, filter compiler, and filter manager.

tcp wrappers - an ip address access control wrapper for TCP services in inted

logdaemon - replacements for rlogin and rshd that allow tcp wrappers style control and logging, drop in replacement for login, rexecd, and ftp that supports s/key and various OTP schemes.

klaxon is a modification of rexec that, instead of executing anything, returns a benign error to the caller, and syslogs the calling host, username, and name of attempted service access.

This version of tftpd is hacked from the 4.3 Reno tftpd with fixed syslogging and per client access control.

socks - networking proxy routines

pidentd - identd verifies the actual user making a tcp connection to another machine

authd is an implementation of RFC 931, the Authentication Server under BSD. authd requires no changes to current code: every connect() and accept() is authenticated automatically, with no loss of efficiency.

portmap - a drop in replacement for portmapper that has access control

rpcbind - a drop in replacement for the sysvr4 portmapper (rpcbind) that prevents people form bypassing NFS export restrictions

xinted is an inetd/tcp_wrapper that also adds many other features, including UDP service access logging, verification, and control.

tcpr - a set of perl scripts that allow ftp and telnet across a firewall

UDPrelay is a daemon process which runs on a bastion system and forwards UDP packets in and out of a firewalled network, as directed by a configuration file. Rsendto.c provides routines Rsendto and Rrecvfrom, which allow tunnelling through the bastion to arbitrary outside hosts. Rsendto/Rrecvfrom communicate with udprelay using UDP packets encapsulated in a wrapper that includes the address of the remote host/port to transfer traffic to.