How I can know the Domain for an IP by PHP?

Question

How I can know the Domain for an IP by PHP?

I have used this code

Answer 1

Your PHP is correct, earthwar.de is the correct answer

eugen@lucidhome:~$ nslookup
> set q=ptr
> 62.75.138.253
Server:     192.168.232.1
Address:    192.168.232.1#53

Non-authoritative answer:
253.138.75.62.in-addr.arpa  name = earthwar.de.

Authoritative answers can be found from:
> 

This ofcourse doesn't mean, that other names (like german-proxy.de) do not point to the same address, but there is no way to find all of them.

Update:

eugen@lucidhome:~$ nslookup 
> set q=a
> german-proxy.de.     
Server:     192.168.232.1
Address:    192.168.232.1#53

Non-authoritative answer:
Name:   german-proxy.de
Address: 62.75.138.253
> earthwar.de.
Server:     192.168.232.1
Address:    192.168.232.1#53

Non-authoritative answer:
Name:   earthwar.de
Address: 91.143.85.129
> 

so this is a good example. Fact is: There aint noth'n ya can do 'bout it, dude!