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How to get Postfix to relay Outlook Out of Office replies with Null Sender?

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  • tswmmeejsdad .
    Hello All, We run a postfix smtp relay that customers use. Customers have reported that they can not send out of offies replies from their Exchange Server.
    Message 1 of 3 , Jul 1, 2013
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      Hello All,
       
      We run a postfix smtp relay that customers use. Customers have reported that they can not send out of offies replies from their Exchange Server.

      Further investigation shows that this is caused by Microsoft changing the way Exchange 2010 delivers out of office replies whereby it replaces the sender with a null sender address to conform to RFC 2298.

      See here:
      http://www.msexchange.org/articles-tutorials/exchange-server-2010/management-administration/automatic-email-server-notifications-in-exchange-server-2010.html

      Our postfix smtp relay is only set to allow users to relay through it if the Source IP address and sender domain contained inside the access-sender file is configured resulting in out of office replies with a null sender address being denied.

      \\ snippet of postfix config

      mynetworks = 127.0.0.0/8, 10.x.x.0/19
      smtpd_sender_restrictions = check_sender_access hash:/etc/postfix/access-sender reject

      My questions is - Is there a way to get postfix to allow Outlook out of office replies with the null sender address to relay through it without adding ALL DOMAINS to the access-sender file(thus making it an open relay)? I've googled around but haven't really found an answer to this question. Not sure if the only way to allow this is to set up some form of SASL authentication between the customer's Exchange Server and our smtp relay.

      We are running postfix 2.3.3

      # postconf -d | grep mail_version
      mail_version = 2.3.3
      milter_macro_v = $mail_name $mail_version

      Thank you in advance.
    • Wietse Venema
      ... Whitelist the Exchange server. /etc/postfix/main.cf: smtpd_sender_restrictions = check_client_access hash:/etc/postfix/access-client check_sender_access
      Message 2 of 3 , Jul 1, 2013
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        tswmmeejsdad .:
        > \\ snippet of postfix config
        >
        > mynetworks = 127.0.0.0/8, 10.x.x.0/19
        > smtpd_sender_restrictions = check_sender_access
        > hash:/etc/postfix/access-sender reject
        >
        > My questions is - Is there a way to get postfix to allow Outlook out of
        > office replies

        Whitelist the Exchange server.

        /etc/postfix/main.cf:
        smtpd_sender_restrictions =
        check_client_access hash:/etc/postfix/access-client
        check_sender_access hash:/etc/postfix/access-sender
        reject

        /etc/postfix/access-client:
        # The Exchange server name or IP address.
        1.2.3.4 OK

        You may also need to do this in smtpd_recipient_restrictions
        (or smtpd_relay_restrictions, if applicable).

        Wietse
      • Wietse Venema
        ... Do not forget to postmap /etc/postfix/access-client . Wietse
        Message 3 of 3 , Jul 1, 2013
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          Wietse Venema:
          > tswmmeejsdad .:
          > > \\ snippet of postfix config
          > >
          > > mynetworks = 127.0.0.0/8, 10.x.x.0/19
          > > smtpd_sender_restrictions = check_sender_access
          > > hash:/etc/postfix/access-sender reject
          > >
          > > My questions is - Is there a way to get postfix to allow Outlook out of
          > > office replies
          >
          > Whitelist the Exchange server.
          >
          > /etc/postfix/main.cf:
          > smtpd_sender_restrictions =
          > check_client_access hash:/etc/postfix/access-client
          > check_sender_access hash:/etc/postfix/access-sender
          > reject
          >
          > /etc/postfix/access-client:
          > # The Exchange server name or IP address.
          > 1.2.3.4 OK
          >
          > You may also need to do this in smtpd_recipient_restrictions
          > (or smtpd_relay_restrictions, if applicable).

          Do not forget to "postmap /etc/postfix/access-client".

          Wietse
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