Re: [Exim] sender_verify_callback & logging: 3.36

On Tue, 3 Sep 2002, Hugh Sasse Staff Elec Eng wrote:

> OK, so I can assume they are taking place but there have been no
> failures yet. I expected something by now given the amount of
> forged hotmail spam we get. Maybe that part of my expectations is
> wrong :-)

Hotmail definitely do reject bad user names... sometimes.

I've seen all three of these behaviours from them in the past, in
response to actual mail or bounces:

- bad recipient reported at RCPT time
- bad recipient reported at end of data
- message accepted, even though known-bad recipient

AIUI, only the first of these can be detected by callback, since it
proceeds no further than that into the SMTP transaction.

Specimen extracted from exim4 log:

sender verify fail for <bbg33617@???>: response to
"RCPT TO:<bbg33617@???>" from mx09.hotmail.com [64.4.49.71] was
550 Requested action not taken:user account inactive

You might want to note that they can also return 5xx to a callback
when the sender's mailbox is full. (this may be a genuine user, so
I'm ***-ing it out):

sender verify fail for <***@hotmail.com>: response to
"RCPT TO:<***@hotmail.com>" from mx01.hotmail.com [65.54.254.145] was
552 Requested action not taken: exceeded storage allocation

We don't take any special action in that case, just treat that as
grounds for rejection also.

But we already had this working in exim3, I can assure you: our
configuration lines for v3 were e.g

sender_verify_callback_domains = partial-dbm;/etc/exim/callback_domains.db
sender_verify_hosts_callback = *

which doesn't look significantly different from yours.

cheers