Here are some of the best networking tools on the Web these days:

1. Network-Tools.com – Ugly interface but a little something for every network tool loving freak.
   
2. Pingdom Tools – The best looking set of network tools, ping, traceroute and page loading tools included.
3. DNS Goodies – Lots of goodies here to love from whois, ip check, ping and more.
   
4. Traceroute.org – Need to do a traceroute from more than one location? The interface is horrible but the info is handy.
5. DNS Stuff – Another list of your generic domain name tools. Also has a paid service for more perks and choices.
6. My Nameserver – Tons of DNS related lookup tools here. Also good to look up abuse, domain name worth and more.
7. DNS Tools – Ping, traceroute, whois and more. I really like the fact you can “search for all” here too.
8. DomainTools.com – Probably my all time favorite, DomainTools.com has everything you could want under the sun.
9. Ajax DNS – Look up your DNS info in a crazy cool ajax powered interface. Not just eye candy here though, good all around resource.
10. IP Tools – Another “we do everything” network tool web site. Dozens of search boxes with dozens of tools.
11. Internet Tools – A handful of Internet query tools so you can do quick searches for things such as various whois searches.
12. Ajax DNS Bench – Drop and give me 20! 6 ajax powered DNS tools here to pick from.
13. My IP Neighbors – Now you can use this site to do a reverse DNS search to find out who else is on your server.
14. Who is Hosting This – Find out the host or server that a domain name is using. Quick and effective (for nosey people only).

Now I wouldn’t recommend trying to use all of these, as many of them preform the same functions. Find the ones that work best for you, and next time you need to do a ping, traceroute or whois search you should be more than ready for the job.