Michael Hannon said...

|We could also just reject email that doesn't arrive via our spam/virus 
|filter, but it's hard to be sure that there isn't some legitimate source 
|of email that's using the 'A' record.  Email is a VERY touchy subject.

It certainly is.

But I tend to define any email that doesn't use the MX
record as "non-legitimate".  Where would you be getting
legitimate email that used the A record?  Have you got
people still sending from homebrew mailers written in
1975, or what?

[Then again, switching to the spam firewall cut down on
the spam (which had become a major pain point) that I
could have gotten away with almost anything, at least
for a while!]

-Miles