DNSDig is a web version of dig. Allows you to query for a domain's DNS from any machine on the internet. Has very comprehensive results.

Online utility for DNS administrators. Test your DNS servers, domain registration, mail and web servers.

A gateway for: finger, nslookup, WHOIS, SSL, traceroute, ping, and dig.

Check the delegation of your domain. Has interesting graphical results.

Provides a free DNS report on your domain name, verifying that your DNS hosting is working properly. Includes over 40 different tests, looking for both minor and major problems.

Handy web-based DNS lookup service, with links.

Many free web-based DNS and domain name tools all in one location. Includes standard DNS lookups, WHOIS/IPWHOIS, and even obscure DNS hosting tests, IPv6, IP-to-country and spam database lookups. Fast and thorough.

Provides ping, traceroute, whois, finger, nslookup, and dig.

A WHOIS domain name search. Check domain name registrations, look up domain names, IP addresses, nameservers, registrars, etc.

iWEBTOOL has frequently used web tools. This easy to use site includes tools ranging from a rank checker to HTML encrypter.

Web-based nslookup tool that lets you look up IP address information. Query their and other DNS domain name servers to look up and find IP address information of computers on the internet.

Provides basic forward and reverse DNS lookups, as well as MX record and server software lookups.

Free tool to check the security of any name server. Requests a name server zone transfer for any domain.

Sitegizmos provides some DNS tools, as well as some other tools useful to webmasters.

Complete DNS traversal check. Shows you every DNS server that is (or may be) used for a DNS lookup, very comprehensive.

You can query any domain here to find the DNS information similar to a nslookup. Links to whois information.

Free online DNS Dig tool, similar to the UNIX "dig" command.