Re: Whitelisting Redux

From: Jorey Bump (no email)
Date: Tue May 01 2007 - 11:10:54 EDT

  • Next message: Wietse Venema: "Re: smtp_connection_cache_on_demand"

    Dennis Putnam wrote:
    >
    > On May 1, 2007, at 10:06 AM, Jorey Bump wrote:
    >>
    >> I'm not sure why you're removing permit_sasl_authenticated, but if you
    >> don't need it, no harm done.
    >
    > I thought that was what you suggested I do.

    No, I meant for you to change the "smtpd_client_restrictions" entry that
    you provided to "smtpd_recipient_restrictions" and remove the redundant
    smtpd_recipient_restrictions from your configuration.

    >> It appears your whitelist is not being consulted. Be sure to issue a
    >> 'postfix reload' after editing main.cf.
    >
    > I do/did. Why would the white list not be consulted?

    It was. The address was wrong.

    >> Put permit_sasl_authenticated back before permit_mynetworks in
    >> smtpd_recipient_restrictions, if you are using authentication for
    >> submission via port 25.
    >
    > It seems to be working without it but I will. In any case this is not
    > effecting the white list is it?

    No.

    >> !=
    >
    > I missed that detail. I didn't think it used the FROM field since that
    > is easily spoofed. The difference is whether the mail originated on a
    > Linux box or Windows box. The bad news is that when I add that to my
    > white list it still doesn't work.

    To be clear, it's using the address provided during MAIL FROM (not the
    From: header), and you're right, that's easily spoofed. But if you want
    to use check_sender_access, that's what we're talking about, the
    envelope sender.

    >> If you want to keep things simple, use this in sender_whitelist:
    >>
    >> bellsouth.net permit_auth_destination

    > I don't really want to open it to all but I might have to try that just
    > to see if anything can get through. Will that also work if the hostname
    > is home.bellsouth.net?

    Refer to Email Address Patterns in:

      man 5 access

    or:

      http://www.postfix.org/access.5.html

    > Actually I need to get this working not just for
    > this user but for others as well. I want to make sure it all works and I
    > understand it before adding more users. These otherwise legitimate ISPs
    > that refuse to take responsibility for spam originating on their
    > networks drive me nuts. I have things pretty tight so we get very little
    > spam leaking through but there are a few legitimate sources that don't.

    Well, I sympathize, but this may be a user issue. They need to complain
    to the ISP or switch. Kudos for trying to solve their problem, but you
    may be taking on a maintenance headache. Of course, you could move your
    RBLs to a scoring system via a policy server or SpamAssassin if they are
    causing you too many problems. Using RBLs isn't required, so I guess you
    do bear some of the responsibility here.

    >> Note that you'll have to put your map *after*
    >> reject_unauth_destination if you use the bellsouth.net address for
    >> outgoing mail (in which case, you should really use their mail server,
    >> instead).
    >>
    >
    > Now I'm confused (as usual). If I send something to
    > it will be rejected? Outgoing mail cannot go to 'bellsouth.net' as that
    > does not resolve to an smtp server. I thought postfix looked up the MX
    > record for that address instead.

    I meant you must do this if you plan to use the bellsouth.net address as
    your sender address for outgoing mail. Outgoing mail *to* bellsouth.net
    is not affected by this configuration.


  • Next message: Wietse Venema: "Re: smtp_connection_cache_on_demand"





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