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Re: Deferred mail and transports and retries

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  • Abhijeet Rastogi
    Hi Wietse, This helps. Half reading is always bad. This clears everything about my doubt. One other thing still remains. I ve multiple smtp services defined
    Message 1 of 10 , Jul 25, 2013
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      Hi Wietse,

      This helps. Half reading is always bad. This clears everything about my doubt.

      One other thing still remains. I've multiple smtp services defined like this. (in master.cf, to use different IPs, selected randomly)

      ob-smtp1   unix    -       -       n       -       -     smtp
        -o smtp_bind_address=1.2.3.4
        -o syslog_name=postfix-smtp1
      ob-smtp2   unix    -       -       n       -       -     smtp
        -o smtp_bind_address=5.6.7.8
        -o syslog_name=postfix-smtp2

      I suppose that if a message delivered via one of the transport and deferred, it'll always be tried via the same "smtp service". Is there a possibility where I can change the smtp service while retrying for a already deferred mail?

      On Thu, Jul 25, 2013 at 6:06 PM, Wietse Venema <wietse@...> wrote:
      Abhijeet Rastogi:
      > Hi Wietse,
      >
      > Thanks for you reply. I may be wrong but I just know what I read in
      > http://tools.ietf.org/html/rfc5321#section-4.5.4
      >
      > >  The sender MUST delay retrying a particular destination after one
      > >  attempt has failed.  In general, the retry interval SHOULD be at

      According to RFC 5321 section 5.1, the sending host should try at
      least two delivery addresses.

      Quote:

         When the lookup succeeds, the mapping can result in a list of
         alternative delivery addresses rather than a single address,
         because of multiple MX records, multihoming, or both.  To provide
         reliable mail transmission, the SMTP client MUST be able to try
         (and retry) each of the relevant addresses in this list in order,
         until a delivery attempt succeeds.  However, there MAY also be
         a configurable limit on the number of alternate addresses that
         can be tried.  In any case, the SMTP client SHOULD try at least
         two addresses.

      If you believe that Postfix should wait between the attempts to
      connect to the first and the second MX address, then you are in
      error.

              Wietse



      --
      Regards,
      Abhijeet Rastogi (shadyabhi)
      http://blog.abhijeetr.com
    • Wietse Venema
      ... You can specify an alternate MTA (with smtp_fallback_relay) for delayed mail. There is no feature to specify an alternate delivery agent for delayed mail.
      Message 2 of 10 , Jul 26, 2013
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        Abhijeet Rastogi:
        > Hi Wietse,
        >
        > This helps. Half reading is always bad. This clears everything about my
        > doubt.
        >
        > One other thing still remains. I've multiple smtp services defined like
        > this. (in master.cf, to use different IPs, selected randomly)
        >
        > ob-smtp1 unix - - n - - smtp
        > -o smtp_bind_address=1.2.3.4
        > -o syslog_name=postfix-smtp1
        > ob-smtp2 unix - - n - - smtp
        > -o smtp_bind_address=5.6.7.8
        > -o syslog_name=postfix-smtp2
        >
        > I suppose that if a message delivered via one of the transport and
        > deferred, it'll always be tried via the same "smtp service". Is there a
        > possibility where I can change the smtp service while retrying for a
        > already deferred mail?

        You can specify an alternate MTA (with smtp_fallback_relay) for
        delayed mail. There is no feature to specify an alternate delivery
        agent for delayed mail.

        The example looks like an attempt to circumvent Yahoo etc. rate
        limits per client IP address. I don't have to make that "easy"
        with Postfix.

        Wietse
      • Abhijeet Rastogi
        You can specify an alternate MTA (with smtp_fallback_relay) for ... Hmm, I was aware of that thing. I ve not used this feature but it s definitely worth
        Message 3 of 10 , Jul 26, 2013
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          You can specify an alternate MTA (with smtp_fallback_relay) for
          delayed mail.  There is no feature to specify an alternate delivery
          agent for delayed mail.


          Hmm, I was aware of that thing.  I've not used this feature but it's definitely worth trying.

          The example looks like an attempt to circumvent Yahoo etc. rate
          limits per client IP address.  I don't have to make that "easy"
          with Postfix.

          It's not about me trying to do spam. I'm part of a hosting company and sometimes our IPs get blocked temporarily when our outbound spam system stops performing for some odd reason.

          Thanks for the help.
           

                  Wietse



          --
          Regards,
          Abhijeet Rastogi (shadyabhi)
          http://blog.abhijeetr.com
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