l4ip is a daemon that extends IPFilter's simple round-robin L4 load balancing with health checks. It takes care of monitoring and dynamically adding and removing ipnat rules in the kernel. It fully supports TCP, UDP, and system()-style executions for health checks, including send/expect scripts, SSL connections, and much more.
connect-tunnel is a simple Perl script that lets you tunnel anything through a CONNECT-aware HTTP proxy. It supports multiple tunnels and multiple connections to those tunnels, and all of the authentication methods that libwww-perl supports (Basic, Digest, and NTLM). It works under Unix and Windows.
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.
http_filter is an HTTP tunnel with filtering and multiplexing. It runs on a firewall, sitting in front of not-so-secure Web servers (like IIS), and it accepts requests, applies a set of rules to them, and allows the requests to be passed through to the back-end Web server only if they pass all filters. The rules can be defined globally or per-server.