How to get the computer name from ip Address?

How to get the computer name from IP Address using php.

Concept :

How to restrict the user with using the system information.,i don't want the IP Address with that restriction.,because it doesn't use for me.,the IP Address are not static everyday it'll changed so i want开发者_JS百科 a system name or something system related.,my basic idea is i want to restrict the user with the access of only one system.,not some other.,(1 user - 1 system) with his/her login details...so this is the concept for my project...

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gethostbyaddr($TheIpAddress);

will do the trick. http://php.net/gethostbyaddr