Softflowd is flow-based network traffic analyser with export

http://www.mindrot.org/softflowd.html

Highly efficient mail filter for identifying spam

http://spamassassin.apache.org/

Traps spammers with a very slow smtp-login and return 4xx error

http://freebsdspamd.sourceforge.net/

Spawns fastcgi applications

http://redmine.lighttpd.net/projects/spawn-fcgi

Sphinx Full-Text Search Engine

http://sphinxsearch.com/

Sphinx Full-Text Search Engine

http://www.sphinxsearch.com/

A standalone JavaScript interpreter from the Mozilla project

http://www.mozilla.org/js/spidermonkey/

Tool for statically checking sourcecode for security vulnerabilities

http://www.splint.org/

SQL database engine in a C library

https://www.sqlite3.org/

HTTP Caching Proxy

http://www.squid-cache.org/

Webmail system which accesses mail over IMAP

http://www.squirrelmail.org/

Protect hosts from brute-force attacks against SSH and other services

https://www.sshguard.net/

Protect hosts from brute force attacks against ssh and other services using ipfilter

http://sshguard.sourceforge.net

Protect hosts from brute force attacks against ssh using ipfw

http://sshguard.sourceforge.net

Protect hosts from brute force attacks against ssh using pf

http://sshguard.sourceforge.net

State Threads Library for Internet Applications

http://state-threads.sourceforge.net/

Advanced IP/IPv6 subnet calculation and discovery

http://www.seccuris.com

Allow others to run commands as root

https://www.sudo.ws/

Generate wrappers for calling C/C++ code from other languages

http://www.swig.org/

Helps to install application configuration files

http://www.Courier-MTA.org/sysconftool/

Network tool designed for high performance and accurate monitoring

http://puck.nether.net/sysmon/

Six utilities for manipulating t1 fonts

https://www.lcdf.org/~eddietwo/type/

Library for manipulating ID3 tags and Ogg comments

http://taglib.github.com/

Tool Command Language

http://www.tcl.tk/

Shell wrapper for tclsh (Tcl)

Tool Command Language

http://www.tcl.tk/

Tool Command Language

http://www.tcl.tk/

Tool Command Language

http://www.tcl.tk/

Packet sniffer which displays TCP information like top(1)

http://BSDforge.com/projects/net-mgmt/tcptrack/

Set of configuration scripts for the TCSH shell

http://tcshrc.sourceforge.net/

Meta-port that creates a site-local TEXMF directory

Texinfo to HTML converter

http://texi2html.cvshome.org/

Typeset documentation system with multiple format output

https://www.gnu.org/software/texinfo/

Tiny/turbo/throttling HTTP server

http://www.acme.com/software/thttpd/

Fixes and tidies up HTML files

https://www.w3.org/People/Raggett/tidy/

Utility to clean up and pretty print HTML/XHTML/XML

http://tidy.sourceforge.net/

Library and program to validate and fix HTML

http://tidyp.com/

Analogous to cdb, but faster

https://www.corpit.ru/mjt/tinycdb.html

A server which provides telnet(1) access to one or more tty ports

Shell wrapper for wish (Tk)

Extremely portable perl-based make utility

http://tmake.sourceforge.net/

A textbased (console) MSN client

http://tmsnc.sourceforge.net/

Enhanced ftp client from NetBSD

https://ftp.netbsd.org/pub/NetBSD/misc/tnftp/

Enhanced FTP server from NetBSD

https://ftp.netbsd.org/pub/NetBSD/misc/tnftp/

Efficient way to prepare zipfiles for BitTorrent

http://trrntzip.sourceforge.net

Trusted Platform Module (TPM) emulator

http://tpm-emulator.berlios.de/

Traditional (K&R-style) C preprocessor

https://www.NetBSD.org/~dholland/tradcpp/

The BPF Traffic Collector

Meta-port for Transmission BitTorrent client

http://www.transmissionbt.com/

Open-source TCG Software Stack

https://sourceforge.net/projects/trousers/