Very useful 2 Online and 2 Desktop network utilities
It a a very comprehensive tool that contains almost everything that you want to do with DNS. This is what DNSstuff says about itself: “We strive to be the fastest, most accurate, and most comprehensive site for DNS, domain name, WHOIS, IP address and other networking tools!”
A Firefox Toolbar is available and should be useful for network admins.
Some of the utilities are similar to DNSstuff but there’re few interesting tools like Browser Mirror: See what your browser reveals and Domain Dossier: Investigate domains and IP addresses, which can also do service scan. Source code is available for most of the utilities.
A free network protocol analyzer that allows you to capture and analyze the live network data. It is the most popular sniffing tool used by network admins.
2. Angry IP Scanner
Very fast, free and open source ip and port scanner. It can scan Mac addresses and resolve net-bios names. The report can be saved in many different formats.