On Mon, 2006-02-13 at 15:14 -0500, Tony Nelson wrote: > I wonder if greylisting pays any attention to MX records? (I just don't > wonder enough to look for myself.) None of the greylisting implementations I am aware of looks at MX records. Typically the way a smtp server farm is handled is by whitelisting those addresses. There are a few relatively large organizations that are known to have such server farms. And the greylisting implementations I have seen deal with this by whitelisting the servers in those server farms so there will be no delay or rejection of the first message. Greylisting still works wonders since the bulk of the spam still appears to come from non-compliant zombie hosts which just spray email and don't bother to check any of the return codes. In combination with spamassassin you can achieve near 100% reduction of spam.
