[Mimedefang] Mimedefang and sendmail queueing

Andrzej Adam Filip andrzej.filip at gmail.com
Wed Jun 10 14:00:18 EDT 2009

Stefan Schoeman <stefan at internext.co.za> wrote:
> I've been using MIMEDefang for some years now and it is just the most
> fabulous tool.
> It's really the tool that allows me to take control of mail, and not
> just anti-virus and anti-spam.
> Thanks again David for writing this - this is really cool.
> I was wondering if someone could perhaps advise me on a new aspect
> that I'd like to implement, and whether MIMEDefang can help me with
> this.
> Basically, I run a number of relay servers that do a couple of things
> with mail (Anti Virus, Anti-Spam, Mail splits, funny redirects and so
> on). What I am finding is that there are times where I would like to
> alter the queuing strategy of the mail. As an example, I may get in
> some really big emails for a given client that I know will take too
> long to deliver to them. What I would like to do with such mails, is
> defer their delivery so that they will rather deliver overnight than
> say right now. It's almost as if I'd like to place such mails into a
> different mail queue, that have differently timed queue runners to
> process them. What I do right now is move the files from my
> /var/spool/mqueue to some other directory (say /var/spool/queue1) and
> then manually start a queue runner as follows: sendmail -q
> -oQ/var/spool/queue1. Or just have a queue runner that processes the
> queue at different intervals than my main mail queue.
> This works, but I'd like to do this a lot better. What I would really
> appreciate is if someone could teach me how to define multiple queues
> for sendmail, and then if someone could advise me on whether it is
> possible in MIMEDefang to indicate to sendmail which mail queue to
> place and email in when the filter is done. It's almost like as if I
> need a MIMEDefang function action_accept(queuename or directory) that
> would indicate to sendmail into which queue to place the message. What
> would be even nicer is if I could access the status of a given queue
> from MIMEDefang, so that I could make decisions on queues based on the
> status of that queue (for example how many messages it contains etc).
> Can the experts on this list please give me their appreciated insights
> on this?

Sendmail can select mailer based (also) on message size.
It can be used to select dsmtp mailer for big messages.
dsmtp deliveries may be triggered via ETRN or 
"sendmail -qR at example.com".
To do reliably "size based routing" "at once" deliveries for such
destination should be turned off. 
Are you ready to accept a few minutes delivery delay?
Sendmail may be configured to ask MIMEDefang (via socket map protocol)
to select mailer based on destination domain, message size and number of
delivery attempts.

For more detailed recipes ask at news:comp.mail.sendmail

"A few years+" ago I have used similar scheme to deliver some (small)
messages via  "instant SMTP" and other (*BIG*) messages via 
"UUCP over TCP". The remote site used "dialup modem speed" connection.

UUCP uses *single* TCP connection so it did not suck all bandwidth of
the remote side during multi hours deliveries of messages queued in 
UUCP queue.

[pl>en: Andrew] Andrzej Adam Filip : anfi at onet.eu
"There is no statute of limitations on stupidity."
  -- Randomly produced by a computer program called Markov3.

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