Hi, I am working on a soap service that I am wanting to implement a domain filter on. Basically, if I get an IP I do not know, I defer a reverse dns lookup and accept their request. The defer does the reverse dns lookup and records whether they were a .edu or not. If I get another request from the same IP I reject or accept their request based on the previous lookup. I have an implementation that is pretty much working, but for some lookups I get an error since the machine does not have ipv6 enabled. (Why is this a dependency?) Here is a little code based on previous postings on rdns. from twisted.names import client addr = '127.0.0.1' # any ip goes here ptr = '.'.join(addr.split('.')[::-1]) + '.in-addr.arpa' d = client.lookupPointer(ptr) d.addCallback(lambda ans, auth, add: log.write(ans[0].payload.name)) Is this approach stupid? :) Any suggestions as to the cleanest approach to this are greatly appreciated! Thanks, Charlie