ServerSniff
http://www.serversniff.net/

ServerSniff.net – Your free “Swiss Army Knife” for networking, serverchecks and routing with many many little toys and tools for administrators, webmasters, developers, powerusers und security-aware users. Benchmarks and informations about servers, routing, IP-Stacks, encryption, security, nameservers and domains. This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.