[Zope] Translate IP to domain?

Hi For marketing reasons, we would like to be able to resolve the IP address of users filling in a web form to their domain name. Is there a Zope product or a python library that allows me to do on the fly IP-to-domain conversion? If the address can not be resolved, I'd like to "keep" the IP address in the result. Zope 2.3 (soon moving to 2.6) Solaris (intel) NO Apache yet, but maybe in the future! Cheers Marc