Frox is a transparent FTP proxy that runs under Linux and *BSD. It should also work on other UNIX OSes that use ipfilter. It supports caching of FTP downloads, either by redirecting through a Squid proxy, or through its own local cache. Downloads may also be transparently scanned for viruses (through an external scanner). Additionally there is an interface for writing scripts to add features or modify frox's behavior, and examples are included to limit download file size and to transparently direct connections to specific hosts to mirror servers. The proxy is written with security in mind, and in the default setup runs as a non-root user in a chroot jail.
ftpUP was designed as a more reliable and quicker acting alternative to dyndns for making Web servers, which are connected via dial-up links, available under a fixed address. It gets your IP on a definable interface and creates an html document containing the current URL of your local server, and uploads it to an existing website. You can also include a logo or other information in the file which is uploaded. Another advantage over dyndns is that the link can point to any URL, ie. your websites can be delivered from anywhere else if your local server goes offline.
Ftwalk is a high level script programming language, very similar to awk, but greatly extended to include a richer type system, object-oriented features, 300+ built-in functions, extensibility through dynamic libraries, etc., which makes it roughly comparable to languages like Perl. It does file tree searches, and was originally used to implement selective redundant copy backup stores. It can be run interactively as a calculator.
fwlogwatch is a packet filter and firewall log analyzer with support for Linux ipchains, Linux netfilter/iptables, Solaris/BSD/HP-UX/IRIX ipfilter, Cisco IOS, Cisco PIX/ASA, Netscreen, Elsa Lancom router, and Snort IDS log files. It can output its summaries in text and HTML and has a lot of options. fwlogwatch also features a realtime anomaly response capability with a Web interface.
Firewall is a set of scripts (firewall, fwup, and fwdown) that implement an ipchains firewall and various forms of network address and port translation. All you have to do is read the policy file and edit it to reflect your topology and filtering policy. It supports many different types of network topology (single host, traditional forwarding, masquerading, port forwarding, alias port forwarding and NAT), up to 10 untrusted interfaces each with their own policy, and over 50 network applications. It also supports centralised administration of multiple remote firewalls (meta-firewall).