Will milter-greylist solve my directory harvest attacks?

Matt Kettler mkettler at EVI-INC.COM
Thu Dec 15 23:16:29 GMT 2005

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shuttlebox wrote:
> On 12/15/05, *Matt Kettler* <mkettler at evi-inc.com
> <mailto:mkettler at evi-inc.com>> wrote:
>     Further follow-up.. milter-sender is the exact opposite of what
>     we're talking
>     about here. That validates the sender, not the recipient.
>     Perhaps milter-ahead could be used here, but not milter-sender.
> I don't use any of them but obviously milter-ahead sounds like a better
> fit. I still don't see how you can invalidate recipients on a relay
> without it though. Sendmail uses its mailertable file to see if it can
> deliver to, for example, an Exchange server further in, it can not
> validate the left side of the mail address and will send everything to
> Exchange.

Blind-forwarding mailservers, like yours, are a pretty major problem.
Particularly since some spammers are abusing them as mail relays through what is
calleda "Reverse NDR" attack.

You really should consider doing something about that ASAP. milter-ahead seems
the easiest way for you.

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