There are so many useful online applications at your need, whenever you need something, just type the keywords into the search box of Google, then it will give you answers. Google is powerful.
The following are some online services I have been using. For fun, and enjoy them.
IP reverse: find out how many websites hosted on the IP which is now hosting your site.
Analyize your webpage, what is the size of your pages.
For guys outside of the mainland of China, use this service to check whether your site is blocked by G.F.W.
The command of Windows does not work very well. It is a good online ping.
http://www.ip.cn/ or http://www.ip2location.com/default.aspx (the latter is more powerful)
Find out where the geographical location of an IP or a website is located.
“Useful Online Services for Web Page Designers”上的5条回复
This site can be used to test how fast your domain (web host) is.