Andrew Norris wrote: > Back to the PTR RR: > > $ dig +short MX bobhoffman.com > 10 mail.bobhoffman.com. > ^^^^^^^^^^^^^^^^^^^^ > $ dig +short A mail.bobhoffman.com > 72.35.68.59 > $ dig +short -x 72.35.68.59 > bobhoffman.com. > ^^^^^^^^^^^^^^^ > > mail.bobhoffman.com != bobhoffman.com > so what? mail.bobhoffman.com is the MX. bobhoffman.com is an RMX. $ host -t mx yahoo.com yahoo.com mail is handled by 1 e.mx.mail.yahoo.com. yahoo.com mail is handled by 1 f.mx.mail.yahoo.com. yahoo.com mail is handled by 1 g.mx.mail.yahoo.com. yahoo.com mail is handled by 1 a.mx.mail.yahoo.com. yahoo.com mail is handled by 1 b.mx.mail.yahoo.com. yahoo.com mail is handled by 1 c.mx.mail.yahoo.com. yahoo.com mail is handled by 1 d.mx.mail.yahoo.com. no one of these is web23004.mail.ird.yahoo.com, ... > This may not be your main problem, but it certainly isn't helping > matters. If we ignore the surrounding IPs (too many without rDNS), he has a very simple setup, that should not cause any problems. > Yahoo seems to be pretty picky on reverse DNS. I had a VPS > running a mail server where the PTR matched the host. I was relegated > to yahoo's spam folder until changed from the default PTR which looked > mildly like a dialup. > generic PTRs are a different matter.