[Mimedefang] Reject 451 (Please try again later) messages

[David F. Skoll]

On Wed, 18 Jun 2003, Bill Randle wrote:

> In the last few days I've seen a flood of "Milter: data, reject=451
> 4.7.1 Please try again later" messages in the mail logs.

This is almost always caused by one of these things:

1) An overloaded mail server.
2) A network test (RBL test, etc.) that's taking too long.
3) A bug in the filter rules.

Given that it's intermittent, I'd guess the problem is (1) or (2).

> 3. here's the confusing part: it looks like sendmail is sending a
> "Please try again later"
>    message to the recipient of the mail, rather than the sender!

No; you're just misinterpreting the logs (which is easy to do.)
Sendmail is replying "Please try again later" to the sending SMTP relay.

> So, in addition to my question in #3 above, it would appear that
> mimedefang got some kind of error, and signal the reject, yet kept
> on processing the message. Is that correct?

If Sendmail or libmilter times out, the multiplexor doesn't know about
that, and will keep processing the message.  It can lead to weird
behavior, as you see.

--
David.