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Re: Block a domain via smtpd_sender_restrictions ?

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  • Benny Pedersen
    ... remove @ if its a subdomain its .example.org DISCARD its just that this helps other spammers use your domain as sender, with exspands the problem
    Message 1 of 4 , Dec 12, 2012
      Frank Bonnet skrev den 12-12-2012 10:39:

      > is it possible to block all a domain using smtpd_sender_restrictions
      > ?
      > @... DISCARD

      remove @

      if its a subdomain its .example.org DISCARD

      its just that this helps other spammers use your domain as sender, with
      exspands the problem
    • /dev/rob0
      ... First, why/who do you want to block? Almost all spam is sent with forged sender addresses, not the actual spammer s address. Blocking by sender address
      Message 2 of 4 , Dec 12, 2012
        On Wed, Dec 12, 2012 at 10:39:23AM +0100, Frank Bonnet wrote:
        > is it possible to block all a domain using
        > smtpd_sender_restrictions ?
        >
        > @... DISCARD

        First, why/who do you want to block? Almost all spam is sent with
        forged sender addresses, not the actual spammer's address. Blocking
        by sender address runs a risk of blocking a real sender. And to the
        point for you as admin: it does not scale well. Any single spam run
        might consist of thousands of sender addresses and domains.

        Second, there is no need to limit this to smtpd_sender_restrictions.
        It might be easier to maintain in smtpd_recipient_restrictions.

        http://www.postfix.org/SMTPD_ACCESS_README.html

        Third, why discard? Why not reject? Discarding mail based on sender
        addresses is reckless. Furthermore it wastes bandwidth and time; just
        DTRT and reject it.

        Fourth, please do not use real Internet domains in examples. There
        are example.{com,net,org,...} for that.

        Finally, see "EMAIL ADDRESS PATTERNS" in the access(5) manual.

        http://www.postfix.org/access.5.html
        --
        http://rob0.nodns4.us/ -- system administration and consulting
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