[Greylist-users] SMTP server pools

[Steven Grimm]

AOL is a great example of a case where it would make sense to alter the
behavior of greylisting based on SPF records. AOL publishes an SPF record
that explicitly lists most of their subnets (I used it as a starting
point for my whitelist) but they also cover some of their hosts using
a rule that says "anything in the mx.aol.com domain is okay." That
rule isn't easily expressed as a simple IP-based whitelist.

It's my expectation that, especially now that SPF looks like it's on
its way to being blessed by the IETF, all the large ISPs that use pools
of mail servers will be publishing SPF records in fairly short order.
Making use of that information where available seems like a no-brainer
to me.

-Steve