On Saturday 02 April 2005 05:32 pm, karl at streetlampsoftware.com wrote: > How > would I go about providing a good, solid *matching* ptr (as in, mail > from AcmeWidget.com reflects to mail.AcmeWidget.com at x.x.x.219 ... > which also happens to be mail.hostco.com) for the bazillion and one > virtual-hosted email accounts on mail.hostco.com? You wouldn't. That's not and never was the purpose of a ptr record. The ptr record is to attach responsibility for the IP#. That's done by pointing it to the hostname. You could have multiple ptr records, but there exists no facility in any DNS or resolution system to match up ptr records with a records. If I recall correctly, behavior in the case of multiple ptr records is undefined. Jeff -- Jeff Lasman, nobaloney.net, P. O. Box 52672, Riverside, CA 92517 US Professional Internet Services & Support / Consulting / Colocation Our blists address used on lists is for list email only Phone +1 951 324-9706, or see: "http://www.nobaloney.net/contactus.html"