At 11:33 -0700 on 04/12/2008, Carl S. Gutekunst wrote about Re: Requiring PTR:
Hector Santos wrote:
Many systems, and naively believed AOL too, I believe used services
like from MAPS RBL which lookup the zone owner to determine if this
was a home or business tier.
They do -- or rather, dynamic vs. static. If you're in the MAPS
dynamic IP range, you won't even get a TCP connection; you'll be
blocked at the firewall.
Unfortunately many so called business tiers are served from a dynamic
block (or at least a dynamic block that is not flagged as business
tier). In fact, many home tiers are allowed to run servers (I am one
as an OptOnline BOOST user) yet are not served from an IP block that
MAPS has flagged as allowed to run an MTA and thus relay messages to
other MTAs or AoL.