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Re: Limit the number of messages sent per connection?

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  • Ralf Hildebrandt
    ... Only in a distan, long gone past: http://www.postfix.org/CONNECTION_CACHE_README.html -- Ralf Hildebrandt (Ralf.Hildebrandt@charite.de)
    Message 1 of 6 , Mar 2, 2008
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      * S P Arif Sahari Wibowo <lists@...>:

      >> Is there any parameter to control the maximum number of messages per
      >> SMTP connection?
      >
      > Hmmm... I thought postfix only send 1 message per SMTP connection.

      Only in a distan, long gone past:
      http://www.postfix.org/CONNECTION_CACHE_README.html

      --
      Ralf Hildebrandt (Ralf.Hildebrandt@...) snickebo@...
      Postfix - Einrichtung, Betrieb und Wartung Tel. +49 (0)30-450 570-155
      http://www.arschkrebs.de
      Fat lady: I was Rubenesque before I was fat. --Metropolitan Museum of Art
    • S P Arif Sahari Wibowo
      ... Ah, that may explain all those emails to yahoo which ended up deferred. :-) So as the OP question, is there any way to limit this feature based on the
      Message 2 of 6 , Mar 2, 2008
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        On Sun, 2 Mar 2008, Ralf Hildebrandt wrote:
        > http://www.postfix.org/CONNECTION_CACHE_README.html

        Ah, that may explain all those emails to yahoo which ended up
        deferred. :-) So as the OP question, is there any way to limit
        this feature based on the number of message per connection, or
        turn off this feature entirely based on domain?

        --
        (stephan paul) Arif Sahari Wibowo
        _____ _____ _____ _____
        /____ /____/ /____/ /____
        _____/ / / / _____/ http://www.arifsaha.com/

        Xinnian Kuaile! 新年快樂 Gongxi Facai 恭喜發財
      • Noel Jones
        ... Postfix smtp connection caching is time based (how long can a connection stay active), not count based, so there is no control to limit the number of
        Message 3 of 6 , Mar 2, 2008
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          Patrick Ben Koetter wrote:
          > The Yahoo! guidelines for establishing SMTP connections to Yahoo! Mail require
          > a maximum of 5 messages per SMTP connection:
          >
          > "Are there any guidelines for establishing SMTP connections to Yahoo! Mail?"
          > <http://help.yahoo.com/l/us/yahoo/mail/postmaster/postmaster-277515.html>
          >
          > I know I can use a special default_destination_concurrency_limit to limit the
          > number of parallel connections (which is not what I need) and $max_use works
          > on incomming connections, but not on outgoing as it seems.
          >
          > Is there any parameter to control the maximum number of messages per SMTP
          > connection?
          >
          > p@rick
          >

          Postfix smtp connection caching is time based (how long can a
          connection stay active), not count based, so there is no
          control to limit the number of messages per connection to some
          arbitrary number.

          http://www.postfix.org/postconf.5.html#smtp_connection_cache_on_demand
          http://www.postfix.org/postconf.5.html#smtp_connection_cache_time_limit

          You can turn off connection caching for a specific transport
          in master.cf.

          abbreviated example:
          # transport
          yahoo.com nocache:

          # master.cf
          nocache unix - - n - - smtp
          -o smtp_connection_cache_on_demand=no

          --
          Noel Jones
        • Noel Jones
          ... After studying yahoo s instructions, it seems they don t intend to penalize you for attempting more than 5 messages per connection, they just disconnect
          Message 4 of 6 , Mar 2, 2008
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            Noel Jones wrote:
            > Patrick Ben Koetter wrote:
            >> The Yahoo! guidelines for establishing SMTP connections to Yahoo! Mail
            >> require
            >> a maximum of 5 messages per SMTP connection:
            >>
            >> "Are there any guidelines for establishing SMTP connections to
            >> Yahoo! Mail?"
            >>
            >> <http://help.yahoo.com/l/us/yahoo/mail/postmaster/postmaster-277515.html>
            >>
            >> I know I can use a special default_destination_concurrency_limit to
            >> limit the
            >> number of parallel connections (which is not what I need) and $max_use
            >> works
            >> on incomming connections, but not on outgoing as it seems.
            >>
            >> Is there any parameter to control the maximum number of messages per SMTP
            >> connection?
            >>
            >> p@rick
            >>
            >
            > Postfix smtp connection caching is time based (how long can a connection
            > stay active), not count based, so there is no control to limit the
            > number of messages per connection to some arbitrary number.
            >
            > http://www.postfix.org/postconf.5.html#smtp_connection_cache_on_demand
            > http://www.postfix.org/postconf.5.html#smtp_connection_cache_time_limit
            >
            > You can turn off connection caching for a specific transport in master.cf.
            >
            > abbreviated example:
            > # transport
            > yahoo.com nocache:
            >
            > # master.cf
            > nocache unix - - n - - smtp
            > -o smtp_connection_cache_on_demand=no
            >

            After studying yahoo's instructions, it seems they don't
            intend to penalize you for attempting more than 5 messages per
            connection, they just disconnect after the 5th and force you
            to make a new connection if you have more to say. They say in
            bold print:
            "Reestablish connections if you do not get an error code"

            If that's really what they are doing, Postfix should deal with
            it gracefully with no changes or special config.

            --
            Noel Jones
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