Not a tool, per se, but a recommended site for getting built-to-length cables of various sorts and colors.

Inkscape supports many advanced SVG features (markers, clones, alpha blending, etc.) and great care is taken in designing a streamlined interface. It is very easy to edit nodes, perform complex path operations, trace bitmaps and much more. We also aim to maintain a thriving user and developer community by using open, community-oriented development.

because it is SVG compatible, you can display it in firefox which makes it very cross-platform. It doesn't have nearly as many stencils as Visio, though.

OSSIM stands for Open Source Security Information Management and compiles more than 15 open source security programs providing all the technology levels to cover the full Security Management cycle.

The OSSIM Sensors integrate powerful open source technology for:

Attack Detection using Snort IDS for real time detection
Vulnerability Scanning using Nessus Vulnerability Scanner
Network Monitoring and Profiling thanks to Ntop
Anomaly Detection with spade, RRD aberrant-behaviour, arpwatch, pads and p0f

Linux-HA aka Heartbeat is a modular package to control high-availability clustering. In spite of it's name it is not limited to Linux (although that is the primary platform), It has an automake based compile and has been used on *BSD, Solaris, and to some extent on AIX as well.

It can hearbeat in multiple ways (UDP broadcast, multicast, and unicast as well as over serial ports, although the serial port heartbeat has been accidently broken in some versions), and over multiple channels (up to 32 as of the time of writing)

It can support sub-second failover

It delays heartbeat checking on initial boot to allow switches time to get through their spanning tree detection timeouts.

UCARP allows a couple of hosts to share common virtual IP addresses in order to provide automatic failover. It is a portable userland implementation of the secure and patent-free Common Address Redundancy Protocol (CARP, OpenBSD’s alternative to the patents-bloated VRRP).

Strong points of the CARP protocol are: very low overhead, cryptographically signed messages, interoperability between different operating systems and no need for any dedicated extra network link between redundant hosts.

SecureLinx Spider™ provides secure KVM over IP (keyboard, video, mouse) management of servers over an IP network. Unlike traditional KVM switches on the market, Spider offers a flexible, scalable and affordable CAT5-based remote access KVM solution in a cable friendly, compact “zero-footprint” package.

The latest addition to the SecureLinx family of IT/data center management products, this KVM over IP solution eliminates server-to-switch CAT5 cable distance limitations, and gives system administrators non-intrusive and cost-effective 24/7 access to servers across a wide variety of IT/network environments: from mission critical servers in high-density data centers, to servers distributed over corporate campuses, multi-floor buildings, remote/branch office sites. Management access, from BIOS to applications, from any web browser anywhere, at any time… guaranteed.

Wackamole is an application that helps with making a cluster highly available. It manages a bunch of virtual IPs, that should be available to the outside world at all times. Wackamole ensures that a single machine within a cluster is listening on each virtual IP address that Wackamole manages. If it discovers that particular machines within the cluster are not alive, it will almost immediately ensure that other machines acquire these public IPs. At no time will more than one machine listen on any virtual IP. Wackamole also works toward achieving a balanced distribution of number IPs on the machine within the cluster it manages.