[Zope] Zserver: IP address based authorization?

Hi, I'm new to Zope and haven't figured out how to allow only a specifed set of IP addresses or hostnames access to a folder. I assume that the "domains" attribute of anonymous user permissions could maybe be used here somehow? I haven't seen any documentation this attribute. Or, would using the GenericUserFolder product be the way to go? It looks like it could be adapted to do this, but the description doesn't mention addres based auth explicitly. Thanks, Robb