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Re: Creating exceptions to greylisting

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  • Reindl Harald
    ... you are aware that OSX 10.6 does no longer get ANY SECURITY update because 10.8 is out? why the hell do people run OSX for a server and not care having one
    Message 1 of 13 , Feb 2, 2013
      Am 02.02.2013 19:37, schrieb Gerben Wierda:
      > Actually, I'm still on
      >
      > /usr/libexec/postfix/greylist.pl
      >
      > as I am using Mac OS X Server 10.6.8 and I haven't dared to upgrade to a higher version of OS X Server as they were busy crippling it in many respects.

      you are aware that OSX 10.6 does no longer get ANY SECURITY update
      because 10.8 is out? why the hell do people run OSX for a server
      and not care having one of the most insecure platforms connected
      to the internet AS SERVER????
    • James Griffin
      ... It s actually very easy to upgrade your Postfix installation by compiling the source code. I have needed to do it numerous times, it s worth getting into
      Message 2 of 13 , Feb 2, 2013
        --> Gerben Wierda <gerben.wierda@...> [2013-02-02 19:37:41 +0100]:

        > Actually, I'm still on /usr/libexec/postfix/greylist.pl
        > as I am using Mac OS X Server 10.6.8 and I haven't dared to upgrade
        > to a higher version of OS X Server as they were busy crippling it
        > in many respects.

        It's actually very easy to upgrade your Postfix installation by
        compiling the source code. I have needed to do it numerous times,
        it's worth getting into the habit of upgrading in this way if you're
        using internet servers.

        You can also use the Macports system. It will provide a way for you
        to use the newer Macports Postfix and stop the Apple installed
        Postfix using launchctl. It's all automated and practically idiot
        proof.


        --
        Primary Key: 4096R/1D31DC38 2011-12-03
        Key Fingerprint: A4B9 E875 A18C 6E11 F46D B788 BEE6 1251 1D31 DC38
      • Gerben Wierda
        Just so there is no misunderstanding: I am unhappy running an older version that is not updated with security fixes anymore and I had planned to upgrade before
        Message 3 of 13 , Feb 2, 2013
          Just so there is no misunderstanding: I am unhappy running an older version that is not updated with security fixes anymore and I had planned to upgrade before now (but not immediately when 10.8 came out as 10.8.0 Server was not what you say trustworthy. I skipped 10.7 server altogether because it is a disaster area.

          I plan to upgrade asap to 10.8 server.

          For now, I came up with:

          smtpd_client_restrictions = permit_mynetworks permit_sasl_authenticated check_client_access hash:/etc/postfix/whitelist_mtaclientdomains reject_rbl_client zen.spamhaus.org permit
          smtpd_recipient_restrictions = permit_sasl_authenticated permit_mynetworks reject_unauth_destination check_client_access hash:/etc/postfix/whitelist_mtaclientdomains check_policy_service unix:private/policy permit

          Which makes sure some clients are permitted before they end up in either RBL or Policy. Just for you more experienced people: is this OK?

          Does macports overwrite what Apple has provided or does it have its own separate tree (like fink used to have, which means you get another job that is: keeping the second tree up to date)?

          G


          On 2 Feb 2013, at 20:36, James Griffin wrote:

          > --> Gerben Wierda <gerben.wierda@...> [2013-02-02 19:37:41 +0100]:
          >
          >> Actually, I'm still on /usr/libexec/postfix/greylist.pl
          >> as I am using Mac OS X Server 10.6.8 and I haven't dared to upgrade
          >> to a higher version of OS X Server as they were busy crippling it
          >> in many respects.
          >
          > It's actually very easy to upgrade your Postfix installation by
          > compiling the source code. I have needed to do it numerous times,
          > it's worth getting into the habit of upgrading in this way if you're
          > using internet servers.
          >
          > You can also use the Macports system. It will provide a way for you
          > to use the newer Macports Postfix and stop the Apple installed
          > Postfix using launchctl. It's all automated and practically idiot
          > proof.
          >
          >
          > --
          > Primary Key: 4096R/1D31DC38 2011-12-03
          > Key Fingerprint: A4B9 E875 A18C 6E11 F46D B788 BEE6 1251 1D31 DC38
        • Stan Hoeppner
          ... /etc/postfix/main.cf: smtpd_recipient_restrictions = ... reject_unauth_destination - check_client_access pcre:/etc/postfix/client_access
          Message 4 of 13 , Feb 2, 2013
            On 2/2/2013 11:10 AM, Gerben Wierda wrote:
            > Dag & Dank Wietse,
            >
            > Can I do perl regex, e.g.
            >
            > outmail\d\d\d.snc\d.facebook.com permit
            >
            > or globbing like
            >
            > outmail*.snc4*.facebook.com

            /etc/postfix/main.cf:
            smtpd_recipient_restrictions =
            ...
            reject_unauth_destination
            -> check_client_access pcre:/etc/postfix/client_access
            check_policy_service unix:private/policy

            /etc/postfix/client_access:
            /.*facebook\.com$/ permit
            ...

            You may want to be more specific. I made my example very generic as
            your expression above seems to miss some of their outbound host rdns,
            such as: outappmail004.snc4.facebook.com

            > And secondly, I also get mail I want to leave through where the sender is an operation like messagelabs, but I want to accept only certain senders using messagelabs, e.g. apg.nl or apg-am.nl. So not so much the client but the from, e.g.
            >
            > @... permit
            >
            > how do I do that?

            You can also do this with a PCRE table. If by "from" you mean MAIL
            FROM, then check_sender_access is what you want:

            http://www.postfix.org/postconf.5.html#check_sender_access

            So in the example above, directly after check_client_access, you'd have:

            check_sender_access pcre:/etc/postfix/sender_access

            and a file with expressions something like:

            /etc/postfix/sender_access
            /.*@apg\.nl$/ permit
            ...

            --
            Stan
          • Stan Hoeppner
            ... That s awfully difficult to read. Try putting each on its own line as in the examples we ve given you. Also, put everything under
            Message 5 of 13 , Feb 2, 2013
              On 2/2/2013 1:55 PM, Gerben Wierda wrote:
              > Just so there is no misunderstanding: I am unhappy running an older version that is not updated with security fixes anymore and I had planned to upgrade before now (but not immediately when 10.8 came out as 10.8.0 Server was not what you say trustworthy. I skipped 10.7 server altogether because it is a disaster area.
              >
              > I plan to upgrade asap to 10.8 server.
              >
              > For now, I came up with:
              >
              > smtpd_client_restrictions = permit_mynetworks permit_sasl_authenticated check_client_access hash:/etc/postfix/whitelist_mtaclientdomains reject_rbl_client zen.spamhaus.org permit
              > smtpd_recipient_restrictions = permit_sasl_authenticated permit_mynetworks reject_unauth_destination check_client_access hash:/etc/postfix/whitelist_mtaclientdomains check_policy_service unix:private/policy permit

              That's awfully difficult to read. Try putting each on its own line as
              in the examples we've given you. Also, put everything under

              smtpd_recipient_restrictions

              and eliminate smtpd_client_restrictions altogether. Now you no longer
              have to duplicate restrictions between them. More importantly, you have
              fine grained control over evaluation order. Thus, this would be much
              better:

              smtpd_recipient_restrictions =
              permit_mynetworks
              permit_sasl_authenticated
              reject_unauth_destination
              check_client_access pcre:/etc/postfix/client_access
              check_sender_access pcre:/etc/postfix/sender_access
              reject_rbl_client zen.spamhaus.org
              check_policy_service unix:private/policy
              ...

              /etc/postfix/client_access:
              /.*facebook\.com$/ permit
              ...

              /etc/postfix/sender_access
              /.*@apg\.nl$/ permit
              ...

              > Which makes sure some clients are permitted before they end up in either RBL or Policy. Just for you more experienced people: is this OK?

              When using separate client and recipient restrictions, as you have
              above, your rbl check against Zen can trigger before your whitelist
              checks, causing a rejection. Using the method I've detailed above
              avoids this situation. Because Postfix performs delayed rejection by
              default, you can put all of your restrictions under
              smtpd_recipient_restrictions and carefully control the order of
              restriction evaluations. I'd guess that every experienced OP on this
              list does it this way. It just doesn't make any sense to do otherwise.

              > Does macports overwrite what Apple has provided or does it have its own separate tree (like fink used to have, which means you get another job that is: keeping the second tree up to date)?

              I have zero experience with MacOS. Sorry.

              --
              Stan
            • Viktor Dukhovni
              ... This is not robust for two reasons, the first is a simple oversight, replace: /.*facebook .com$/ permit with / .facebook .com$/ permit since
              Message 6 of 13 , Feb 2, 2013
                On Sat, Feb 02, 2013 at 03:34:30PM -0600, Stan Hoeppner wrote:

                > check_client_access pcre:/etc/postfix/client_access
                > ...
                >
                > /etc/postfix/client_access:
                > /.*facebook\.com$/ permit

                This is not robust for two reasons, the first is a simple oversight,
                replace:

                /.*facebook\.com$/ permit

                with

                /\.facebook\.com$/ permit

                since "notfacebook.com" is not "facebook.com" and any SMTP client
                in the real facebook.com domain would be a proper sub-domain.

                The second issue is not easy to fix, transient DNS lookup errors
                (timeouts, ...) may result in a client hostname of "unknown" rather
                than <mumble>.facebook.com. In such cases the whitelist entry will
                not apply. Generally this is a problem as messages may be erroneously
                rejected due to a transient error. In this case, provided the whitelist
                entry is solely to avoid greylisting, this is OK, since greylisting
                is responds with temporary (4XX) error codes.

                --
                Viktor.
              • Stan Hoeppner
                ... It wasn t intended to be robust Viktor, but quite the opposite. ... I guess you missed what came directly after that... ... Sometimes, when a kid asks for
                Message 7 of 13 , Feb 2, 2013
                  On 2/2/2013 3:50 PM, Viktor Dukhovni wrote:
                  > On Sat, Feb 02, 2013 at 03:34:30PM -0600, Stan Hoeppner wrote:
                  >
                  >> check_client_access pcre:/etc/postfix/client_access
                  >> ...
                  >>
                  >> /etc/postfix/client_access:
                  >> /.*facebook\.com$/ permit
                  >
                  > This is not robust for two reasons, the first is a simple oversight,
                  > replace:

                  It wasn't intended to be robust Viktor, but quite the opposite.

                  > /.*facebook\.com$/ permit
                  >
                  > with
                  >
                  > /\.facebook\.com$/ permit
                  >
                  > since "notfacebook.com" is not "facebook.com" and any SMTP client
                  > in the real facebook.com domain would be a proper sub-domain.

                  I guess you missed what came directly after that...

                  On 2/2/2013 3:08 PM, Stan Hoeppner wrote:
                  > You may want to be more specific. I made my example very generic as
                  > your expression above seems to miss some of their outbound host rdns,
                  > such as: outappmail004.snc4.facebook.com

                  Sometimes, when a kid asks for an apple, it's better to give him a
                  rotten one, so as to teach him to pick his own fresh apples from the
                  tree. I.e. I gave him a rotten example of a regex hoping/assuming he'd
                  do some legwork and create his own set of fully qualified expressions to
                  meet his needs.

                  --
                  Stan
                • James Griffin
                  ... Sure, I can understand that. ... No, Macports does not overwrite what Apple has installed and yes, it does use its own separate filesystem as Fink does;
                  Message 8 of 13 , Feb 3, 2013
                    --> Gerben Wierda <gerben.wierda@...> [2013-02-02 20:55:42 +0100]:

                    > Just so there is no misunderstanding: I am unhappy running an
                    > older version that is not updated with security fixes anymore and
                    > I had planned to upgrade before now (but not immediately when 10.8
                    > came out as 10.8.0 Server was not what you say trustworthy. I skipped
                    > 10.7 server altogether because it is a disaster area. I plan
                    > to upgrade asap to 10.8 server.

                    Sure, I can understand that.

                    > Does macports overwrite what Apple has provided or does it have
                    > ts own separate tree (like fink used to have, which means you get
                    > another job that is: keeping the second tree up to date)?

                    No, Macports does not overwrite what Apple has installed and yes,
                    it does use its own separate filesystem as Fink does; it's under
                    /opt/local. However, they do specify that have programs installed
                    in /usr/local (i.e. manually installed or otherwise) causes issues
                    when using Macports. Totally OT, sorry about that.

                    It does provide you a way of keeping installed programs up-to-date
                    which is why I suggested it. You simply use launctl/Launchd to
                    select which MTA you use; i.e. the Macports installed version or
                    the Apple preinstalled version.
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