Inspired Mashable Gmail Toolbox and other Toolbox series. Here I have my DNS toolbox listed below. I will probably update the list when I get more.

1. DNSStuff: Useful for DNS Admins and web Admins
2. Some free services are DNSreport, DNS Lookup (A, MX, NS, SOA, etc.). Traceroute, Email Test and many more ( around 20+ free services)
3. OpenDNS: OpenDNS is a safer, faster, smarter and more reliable way to navigate the Internet. Free DNS service. Our service is free and requires nothing to download.
4. Who is Hosting? Who Is Hosting This is a tool that enables you to find out who is hosting any web site. Simply type in any domain name, and you’ll get a link to the company that’s hosting this particular domain.
5. No-IP : Reliable dynamic DNS and web redirection for your own domain name. Many other services related to Dynamic IP binding.
6. Free DNS:Free DNS Hosting, Dynamic DNS Hosting, Static DNS Hosting, subdomain and domain hosting.
7. DynDNS - A free DNS service for those with dynamic IP addresses
8. MX Toolbox:Everything about MX record lookup
9. Tutorial : Listed and explained all DNS parameters. A must read for DNS admins.
10. Tutorial: DNS tips and tricks