Tenable Nessus is a world-leader in active vulnerability scanners. It features high-speed discovery, configuration auditing, asset profiling, sensitive data discovery, and vulnerability analysis of your security posture. Nessus scanners may be distributed throughout an entire enterprise, inside DMZs, and across physically separate networks. It is free of charge for personal use in a non-enterprise environment.
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.