Question : get hostname from IP address

I know the IP addresses for several computers on my LAN but can't find a way to translate the IPs into hostnames.  Just a simple switch & router, class C network.  No Active Directory or anything like that.  I have tried "ping -a xxx.xxx.xxx.xxx" but that does not return the hostname.  Is there a way I can do this on my network as it is now?  If not, would would be needed before this would be possible.

Thanks!

Answer : get hostname from IP address

Any other solutions that might work for finding the Linux hostnames?