HTTPGate is a filtering HTTP Gateway originally intended to enchange user's privacy when surfing on the net, but it can also be used to avoid censorware systems in web browsing. HTTPGate operates on a user definable internet port where the user connects using a web browser. The main page shows a text box and a set of options user can choose to avoid transmitting some information during client/server negotiation.
GNU Anubis is an SMTP message submission daemon. It represents an intermediate layer between the mail user agent (MUA) and mail transport agent (MTA), receiving messages from the MUA, applying to them a set of predefined changes, and finally inserting modified messages into an MTA routing network. The set of changes applied to a message is configurable on a system-wide and per-user basis. The built-in configuration language used for defining sets of changes allows for considerable flexibility and is easily extensible.
Proxytunnel is a program that connects stdin and stdout to a server somewhere in the Internet through an industry standard HTTPS proxy. It's mostly used as a backend for OpenSSH's ProxyCommand, and as a proxy backend for Putty. It can also be used for other proxy-traversing purposes.
Anti-censorship tools (proxyTools) consists of a huge Perl application (localProxy) and a set of tools to analyze the user's network (proxies, firewall rules, name servers, etc.). LocalProxy abstracts external services in an uncensored, reliable, fast manner to the localhost, where they may be used by standard clients (Web browsers, Usenet news clients, SOCKS-capable clients, etc.). Various combinations of strategies are tried to ensure the non-censored nature of the information, and multiple, parallel services (e.g. HTTP proxies) are used to ensure reliability and speed. The tools are capable of automating collection of the data required for localProxy. LocalProxy builds a configuration for the user and dynamically adjusts to using the fastest strategies and proxies available to it. The tools are useful for network analysis (firewall rules, proxy capabilities, etc.) independently of localProxy.
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.
ProxIRC aims to be a proxy through which one can connect to an IRC server while also being able to connect to other instant messaging systems. Right now, partial support is offered for Microsoft's MSN using libMSN. Any IRC client can be used. Status of connected users in the MSN is made thanks to a virtual channel created by the proxy. When a user wants to talk to a friend from MSN, they /join #friend and talk. The rest of the channels are provided by a true IRC server and directly forwarded by the proxy. Only messages outgoing from the IRC client (which may be anyone) are parsed to look for information intended for the proxy. Information not useful for the proxy is forwarded to the IRC server.