Libconnect is a simple library wrapper written in assembly language that intercepts the calls applications make to establish TCP connections and transparently proxies them as necessary. Existing applications can use this library without any recompilation or modification. If you provide multiple proxies they will be cycled connection after connection.
PostArmor (formerly MailArmor) helps to keep your electronic mailbox free of spam: it looks at the relevant parts of your email before it leaves the mail server, and lets the legitimate messages pass through undisturbed, while leaving suspect messages on the server to be reexamined later or just deleted after a while. It works as a POP3 email proxy, with support for POP, APOP, and IMAP servers. It supports SpamCop reports and blacklist, and the ORDB and OSIRUSOFT blacklists.
JSpamfilter is software that intercepts connections from remote Internet mail servers before they can connect to your mail server. The originating IP address for the inbound connection is then checked against one of the DNS-based SPAM Blackhole (DNSBL) lists maintained on the Internet by various organizations. If the check passes, the connection is allowed to proceed to your mail server; if it fails, the connection is told that the mail server is unavailable, then dropped.
ffproxy is a filtering HTTP/HTTPS proxy server. It is able to filter by host, URL, and header. Custom header entries can be filtered and added. It can even drop its privileges and optionally chroot() to some directory. Logging to syslog() is supported, as is using another auxiliary proxy server. An HTTP accelerator feature (acting as a front-end to an HTTP server) is included. Contacting IPv6 servers as well as binding to IPv6 is supported and allows transparent IPv6 over IPv4 browsing (and vice versa).
PHP-Proxy is a PHP script for taking Web pages from one server, so that your main server is protected if the Web server is overloaded from things like DOS attacks. It is also very useful if you have a machine behind a firewall that you want to be your server for Web pages, provided that the machine running the proxy has port 80 open. Finally, there is encryption to defeat filters on specific words if need be.
NACS provides you a comfortable and secure way to provide untrusted computers access to your TCP/IP-based (v4) LAN/WAN. The system guarantees that only registered users are able to use network resources. In contrast to other solutions, like PPTP or IPsec, it is not necessary to install program-specific client software. The client machines only need a DHCP client (automated networkconfiguration) and an SSL capable Web browser. The server needs a 2.4 kernel, Jakarta-Tomcat Servlet Engine, JDK 1.3/JDK 1.4, Apache, MySQL, and firewall which secures your network in general. NACS gets its login and password data from a normal Linux-style passwd file. This implementation supports the integration of other authentication mechanisms (such as LDAP).
Privoxy is a Web proxy based on Internet Junkbuster with advanced filtering capabilities for protecting privacy, filtering Web page content, managing cookies, controlling access, and removing ads, banners, pop-ups, and other obnoxious Internet junk. Privoxy has a very flexible configuration and can be customized to suit individual needs and tastes. Privoxy is useful for both stand-alone systems and multi-user networks.