gethostby... functions

[Anon]

I can get the ip address from a name using gethostbyname. But, if I put the same address, in many cases, I do not get the hostname using gethostbyaddr. For example, www.techpark.net returns 100.100.100.254. But, the address won't return the name. Why?

[foxden]

That is a reverse DNS function, it is blocked or filtered in some instances.