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Re: Snapshot 20130517

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  • Wietse Venema
    ... For whitelisting I used a wild-card A record, and for timeout testing I used an NS record that resolves to a firewalled port (a black hole). This
    Message 1 of 25 , May 18, 2013
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      /dev/rob0:
      > On Fri, May 17, 2013 at 10:06:38PM -0400, Wietse Venema wrote:
      > > Wietse Venema:
      > > > I can change postscreen to also use partial scores for
      > > > whitelisting of non-DNS tests, and thereby make whitelisting
      > > > of non-DNS tests consistent with DNS-based blocking (that's one
      > > > less WTF factor). This requires minor code duplication.
      > >
      > > Released as snapshot 20130517.
      >
      > For testing I reenabled PSBL, and I'll see what comes in overnight.
      > I thought I could make my own pseudo-DNSBL on a random IP address
      > with blocked ports 53, but I need to set up an NS record to point to
      > that. I'll do that tomorrow if results tonight are inconclusive.

      For whitelisting I used a wild-card "A" record, and for timeout
      testing I used an NS record that resolves to a firewalled port (a
      black hole).

      This confirmed that postscreen will now use partial scores to
      whitelist pending non-dnbsbl tests.

      I can make those domain names available for general testing (but
      not now as I am in the middle of a copper-to-fiber conversion).

      Wietse
    • /dev/rob0
      Still watching logs, this one just passed by. Probably unrelated to the changes in 20130517, but I was curious about it: May 19 13:24:20 harrier
      Message 2 of 25 , May 19, 2013
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        Still watching logs, this one just passed by. Probably unrelated to
        the changes in 20130517, but I was curious about it:

        May 19 13:24:20 harrier postfix/postscreen[3533]: CONNECT from [188.42.15.19]:48706 to [207.223.116.211]:25
        May 19 13:24:26 harrier postfix/postscreen[3533]: NOQUEUE: reject: RCPT from [188.42.15.19]:48706: 450 4.3.2 Service currently unavailable; from=<bounce@...>, to=<munged@...>, proto=ESMTP, helo=<mail18.consumer-news123.com>
        May 19 13:24:26 harrier postfix/postscreen[3533]: PASS NEW [188.42.15.19]:48706
        May 19 13:24:26 harrier postfix/postscreen[3533]: DISCONNECT [188.42.15.19]:48706

        All is well and good for a non-whitelisted host, but apparently it
        was too quick in coming back to the secondary MX IP address ...

        May 19 13:24:26 harrier postfix/postscreen[3533]: CONNECT from [188.42.15.9]:33610 to [207.223.116.214]:25
        May 19 13:24:26 harrier postfix/postscreen[3533]: WHITELIST VETO [188.42.15.9]:33610

        ... all in the same second, but according to syslog, sequentially
        after having earned whitelist status.

        May 19 13:24:32 harrier postfix/postscreen[3533]: NOQUEUE: reject: RCPT from [188.42.15.9]:33610: 450 4.3.2 Service currently unavailable; from=<bounce@...>, to=<munged@...>, proto=ESMTP, helo=<mail8.consumer-news123.com>
        May 19 13:24:32 harrier postfix/postscreen[3533]: DISCONNECT [188.42.15.9]:33610

        Another six seconds pass before this one is turned away, which
        suggests that the greet pause was repeated. Makes sense, because
        "WHITELIST VETO" means it was not seen before.
        --
        http://rob0.nodns4.us/ -- system administration and consulting
        Offlist GMX mail is seen only if "/dev/rob0" is in the Subject:
      • Wietse Venema
        ... postscreen does not find the client IP address in the permanent postscreen_access_list, does not find client the IP address in the temporary
        Message 3 of 25 , May 19, 2013
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          /dev/rob0:
          > Still watching logs, this one just passed by. Probably unrelated to
          > the changes in 20130517, but I was curious about it:
          >
          > May 19 13:24:20 harrier postfix/postscreen[3533]: CONNECT from [188.42.15.19]:48706 to [207.223.116.211]:25
          > May 19 13:24:26 harrier postfix/postscreen[3533]: NOQUEUE: reject: RCPT from [188.42.15.19]:48706: 450 4.3.2 Service currently unavailable; from=<bounce@...>, to=<munged@...>, proto=ESMTP, helo=<mail18.consumer-news123.com>
          > May 19 13:24:26 harrier postfix/postscreen[3533]: PASS NEW [188.42.15.19]:48706
          > May 19 13:24:26 harrier postfix/postscreen[3533]: DISCONNECT [188.42.15.19]:48706

          postscreen does not find the client IP address in the permanent
          postscreen_access_list, does not find client the IP address in the
          temporary postscreen_cache_map, logs the "all tests passed" status,
          updates the temporary postscreen_cache_map with the expiration time
          for each test, and forgets the test results.

          > All is well and good for a non-whitelisted host, but apparently it
          > was too quick in coming back to the secondary MX IP address ...
          >
          > May 19 13:24:26 harrier postfix/postscreen[3533]: CONNECT from [188.42.15.9]:33610 to [207.223.116.214]:25
          > May 19 13:24:26 harrier postfix/postscreen[3533]: WHITELIST VETO [188.42.15.9]:33610
          >
          > ... all in the same second, but according to syslog, sequentially
          > after having earned whitelist status.

          postscreen logs "CONNECT from", does not find the client IP address
          in the permanent postscreen_access_list, and does not find the
          client IP address in the temporary postscreen_cache_map. Therefore
          this is handled as a non-whitelisted client that connects to the
          "wrong" IP address.

          Why wasn't the client IP address found in the temporary
          postscreen_cache_map? Maybe silent corruption of the cache database.

          Wietse
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