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*_destination_concurrency_limit help

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  • Devin Nate
    Hi all; I am trying to understand the meaning of the transport_destination_concurrency_limit parameters, where transport is the name of a transport in
    Message 1 of 1 , Feb 27 8:56 PM
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      Hi all;

      I am trying to understand the meaning of the
      transport_destination_concurrency_limit parameters, where "transport" is the
      name of a transport in master.cf or default (please read below, I understand
      it in some circumstances, but not all). I've read and studied the
      documentation in postconf(5), transport(5), qmgr(8), and pipe(8) and I'm
      still struggling with a few instances of using this.

      What I do understand (and please let me know if this is wrong) is that where
      a transport that uses domains is involved (e.g. smtp client or lmtp client,
      and the "domain" is a domain that it is being delivering to):
      (a) where transport_destination_recipient_limit > 1, then this controls
      how many concurrent deliveries will be made via the specified transport to
      the domain being delivered to.
      (b) where transport_destination_recipient_limit = 1, then this controls
      how many concurrent deliveries will be made via the specified transport to
      the recipient at recipient@domain being delivered to.

      What I don't understand is what happens where a transport doesn't deal with
      a domain, per se. So in this instance, we are using
      smtpd_client_restrictions configured with check_client_access, and have a
      FILTER result. In particular, we have:

      --

      main.cf:
      smtpd_client_restrictions =
      permit_mynetworks
      check_client_access hash:/etc/postfix/pop_before_smtp
      check_client_access hash:/etc/postfix/client_access
      check_client_access static:FILTER spamc:dummy
      permit
      spamc_destination_concurrency_limit = ???? (I don't know the meaning of
      this)
      spamc_destination_recipient_limit = 1024 # 1024 less than the arg limit
      of the shell

      master.cf
      spamc unix - n n - - pipe
      flags=Rq user=nobody argv=/etc/postfix/spamc.sh -f ${sender} --
      ${recipient}

      spamc.sh is roughly the same as a simple post-queue content filtering
      script.

      --

      When used like this, there isn't a destination domain per se (as I wrote).
      At best, the left hand side (LHS) of the check_client_access expression is
      the client domain or ip address of the client being check as part of
      check_client_access.

      So, does the "destination" refer to:
      1. The spamc transport period? (unlikely, but I suppose possible)
      2. The domain name of the LHS?
      3. The ip address of the LHS?
      4. Does qmgr check the list of recipients in ${recipient} and keep track of
      the domains being delivered to in this list, and evaluate the limit against
      that list?
      5. The total number of instances this transport program may be running for?
      (again, I don't see this being the case as it's defined in master.cf and
      $default_process_limit)
      6. some other method?

      Any advice/help will be greatly appreciated!

      Thanks,
      Devin Nate




      --

      ____________________________________________

      Devin Nate
      Technical Services Manager
      CLINICARE Corporation

      http://www.clinicare.com/ <http://www.clinicare.com/>
      mailto:devin.nate@... <mailto:devin.nate@...>

      tel: (403) 259-2273 x240
      fax: (403) 259-2400

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      Calgary AB 2TL 2K7
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