performing reverse DNS lookup with InetAddress

[Madhur Ahuja]

Hello

I use *InetAddress.getByName("host").getHostName()* to get the host name
from IP Address .
Problem is that this method doesn't do error checking i.e. when a IP address
cannot be resolved, it returns the IP Address in text format rather than the
exception.

Is there any way I can detect whether IP address was successfully resolved
or not.



--
Winners dont do different things, they do things differently.

Madhur Ahuja
India

Homepage : http://madhur.netfirms.com
Email : madhur<underscore>ahuja<at>yahoo<dot>com

 

[Paul Lutus]

Hello

I use *InetAddress.getByName("host").getHostName()* to get the host name
from IP Address .
Problem is that this method doesn't do error checking i.e. when a IP
address cannot be resolved, it returns the IP Address in text format
rather than the exception.

Is there any way I can detect whether IP address was successfully resolved
or not.

Say again? You just explained how to do it, then asked how to do it. If the
call returns an IP address, not a site name, the address wasn't resolved.

Using:

String s = InetAddress.getByAddress(new byte[] {(byte)64,(byte)226,(byte)42
(byte)135}).getHostName();

If after the call, String s equals a textual IP, the lookup failed:

if (s.matches("\\d+\\.\\d+\\.\\d+\\.\\d+"))
{
System.out.println("Address not resolved.");
}