kipmp is an IPMP-like daemon that will flip a server's IP address between a primary and backup network interface based on the result of active probes against a (hopefully redundant) target like a default gateway. It is useful when one server is connected to multiple switches in the same network and higher availability is desired.
Webtunnel is a network utility that encapsulates arbitrary data in HTTP and transmits it through a Web server. In that regard, it is similar to httptunnel. However, its server component runs in the context of a Web server as a CGI application (with optional FastCGI support), so it does not need its own port. It supports most things that the Web server supports, such as authentication, HTTP 1.1, HTTPS, and client certificates. It uses simple requests and responses so it works seamlessly through forward and reverse proxies.
The Mobile Web Proxy is a (CGI) tool to make more Web pages available from some mobile devices (cell phone Web browsers, etc.). It employs tag cleaning and paging so that Web pages it can access have far greater chances of being rendered on devices that cannot display overly large or complex pages. It is simple, but it seems to substantially extend the portion of the Web available from devices that otherwise display messages like "413: Page cannot be displayed."
Openwsman provides an implementation of the Web Services Management specification and expose system management information on the Linux operating system using the WS-Management protocol. It is based on a suite of Web services specifications and usage requirements that exposes a set of operations focused on and covering all system management aspects.
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.
Dummynet is a flexible tool originally designed for testing networking protocols, and since then (mis) used for bandwidth management. It simulates/enforces queue and bandwidth limitations, delays, packet losses, and multipath effects. It also implements a variant of Weighted Fair Queueing called WF2Q+. It can be used on user's workstations, or on FreeBSD machines acting as routers or bridges.
Argus is a system and network monitoring application. It will monitor nearly anything you ask it to monitor (TCP + UDP applications, IP connectivity, SNMP OIDS, etc). It presents a clean, easy-to-view Web interface. It can send alerts numerous ways (such as via pager) and can automatically escalate if someone falls asleep.