RANCID (Really Awesome New Cisco confIg Differ) collects a router's (or device's) configuration, including software and hardware (cards, serial numbers, etc.), and uses CVS to display differences from a previous collection. It supports Cisco routers, Juniper routers, Catalyst switches, Foundry switches, Redback NASs, and ADC EZT3 muxes. The Beta version currently includes support for Bay Networks (nortel) routers and Extreme switches. Rancid also includes a lookingglass and the device login scripts may be used to automate a number of tasks.
Archivist is a network device configuration archiving and versioning program. It uses Subversion as its revision control system. Its multithreaded design makes it quite fast and thus suitable for operation on large networks with thousands of network devices. It supports Cisco IOS, Cisco CatOS, Juniper JUNOS, and Brocade/Foundry MLX series, but it can be easily extended to support any SSH or telnet-based network device by creating your own config download and post-processing scripts.