fk is an application proxy suite designed for building IP gateways. Ultimately, the intent is to provide a free software replacement for the TIS firewall toolkit.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.
A new flexible access-control facility, support for the IDSA intrusion detection system, ftp gateway support for upload, and a code cleanup have been included.
A semantic weakness in the ACL tools and some embarassing bugs in the ftp proxy have been fixed. Transfer type and port restrictions for the ftp proxy have been implemented (SIZE really works now). This release also features some initial correctness auditing and removal of unexpected aborts.
This is the initial announcement, making available a TCP plug proxy, POP3 and FTP gateways, an ident server, a network ACL facility, and some log-checking tools.