DCC Rejecting Good Mail?

Vernon Schryver vjs@calcite.rhyolite.com
Sat Mar 13 21:47:52 UTC 2010

> From: Bob Cobb 

> For some reason DCC is rejecting mail from good domains/emails, even
> after white listing them in whiteclnt or sendmail's access file.  Here's
> the error message in the sendmail log,
> Milter: data, reject=550 5.7.1 OK: Sent to DCC

That suggests that sendmail is telling dccm that the message is spam
as far as sendmail is concerned and that the default "option MTA-last"
is in effect so that sendmail overrides the dccm whiteclnt file.

> I've checked the inbox and it doesn't contain the email, so I'm
> assuming it didn't get delivered.  It weird because, later on other
> users from that same domain started to experience the same effect.
> Here's my white list configs:
> whiteclnt:
> ok      ip      host.domain.com
> ok      substitute mail_host host.domain.com
> access:
> host.domain.com            DCC:OK
> host.domain.com - some other mail server

It should not necessary to whitelist the SMTP envelope Mail_From
domain name in both the sendmail access database and the dccm whiteclnt file.

To whitelist using the sendmail access db, you need to modify sendmail.mc/cf
with `/usr/var/dcc/libexec/hackmc -O` or equivalent
and use a line like this without "DCC:"

    host.domain.com            OK

The current result of hackmc has "host DCC:message", "host DCC:reject message"
and so forth all meaning "sendmail hates host and should tell dccm"

In general, see the comments in hackmc.

If changing the /etc/mail/access (or wherever) file does not fix the
problem, these questions might give clues:

   - has sendmail.cf/mc been adjusted with hackmc or an equivalent?
	If so, with which hackmc args?

   - does /var/dcc/whiteclnt or relevant per-user 
       /etc/mail/userdirs/local/$USER/whiteclnt files contain 
       "option MTA-first" or "option MTA-last" ?
       (see the main dcc man page concerning those)

  - what do the /var/dcc/log files for the mail messages say?

I'll change the sendmail.cf rules added by hackmc in the next release
so that "host DCC:OK" is parsed as "host is OK for both sendmail & DCC"
instead of the current "host is bad and the error message to give dccm is OK"

Vernon Schryver    vjs@rhyolite.com

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