DCC and qmail turns out to be easy

Vernon Schryver vjs@calcite.rhyolite.com
Mon Dec 22 00:54:02 UTC 2003

> From: "John R Levine" <johnl@iecc.com>

> ...
> The one thing this doesn't do is selective acceptance since qmail-qfilter
> doesn't provide a way to edit the envelope.  That's not much of a problem
> here since my users rarely disagree about what's spam, but if I wanted to
> adjust it to be called directly with the QMAILQUEUE interface, I could do
> that, too.

I hope "selective acceptance" refers to delivery and not to telling
the distant, sending SMTP client that the local SMTP server is
rejecting the message for some recipients and accepting it for other.
After the DATA command the SMTP server can only say 250-OK to accept
the message for all recipients when they were presented with the
envelope, 4yz to say the SMTP client should retransmit later to all
recipients, or 5yz to say that the message is being rejected for all
recipients.  This characteristic of the SMTP protocol.

> Question: the dccifd man page refers to a -a flag to say whether to fail
> or just note messages that are bulky, but the dccifd code doesn't support
> such a flag.  Is that a bug in the doc or in the code?

That's a bug in the dccifd man page.  I wrote dccifd by starting
with a copy of the dccm source including its man page.
There is no `dccifd -a` because I figured that the MTA could decide
whether it wants to do something else when dccifd says "reject."

> Another question: are users expected to edit the -U whiteclnt files?  Does
> dccifd have to be able to write them?  Should I fudge it by making them
> group writable?  On this host, most of the users have shell accounts with
> their own uids.  The others are mail-only, so I can figure out how to do
> those through CGI.

I think the best tactic is to use something like the CGI scripts in
/var/dcc/cgi-bin to let users examine their own logs and adjust their
own, per-user whitelists from an HTTP browser.  There is a README file in 
that directory that talks about how to use those scripts with Apache.
Some organizations are using those scripts or scripts like them.
See http://www.dcc-servers.net/dcc/dcc-tree/cgi-bin/

Vernon Schryver    vjs@rhyolite.com

More information about the DCC mailing list

Contact vjs@rhyolite.com by mail or use the form.