high volume/speed gethostbyaddr how?

[Dan Polak]

Gethostbyaddr blocks by default, this means that there is an appreciable 
delay before it returns.
If you need to lookup a fair number of hostnames gethostbyaddr is much 
too slow.
Using select or the asyncore library might be the way to do it, but I 
don't really understand how to make that work.
What is a good way to retrieve the names for a 100 hosts within a few 
seconds?

Dan