hmms PTR record up the poop?
Actually I see the MX record for .com and .org domains is different for each:
mx2.balanced.randy.mail.dreamhost.com. [Preference = 0]
mx1.balanced.randy.mail.dreamhost.com. [Preference = 0]
ASPMX.L.GOOGLE.COM. [Preference = 10]
Screwed my login cookie as well and I couldn't remember what email address I had used in my login!
Reverse PTR lookups are a bit hit and miss for an antispam technique anyway. "Greylisting" seems to work well although it delays email delivery.