Re: OT: spammers are using my domain again

From: Thomas Zehetbauer (thomasz_at_hostmaster.org)
Date: 10/08/04

  • Next message: Richard Houston: "Duel Monitor (not a laptop)" 
    To: For users of Fedora Core releases <fedora-list@redhat.com>
Date: Fri, 08 Oct 2004 22:27:04 +0200

    On Fre, 2004-10-08 at 15:45 -0300, Trevor Smith wrote:
    > When I'm at home, and I try to send mail through my haligonian.com
    > smtp server (hosted in Quebec, remember), I can not succeed (can't
    > recall the error and I'm not home now).

    This means that either the company hosting your domain does not allow
    you to relay mail from your home account or your telco filters smtp
    connections to foreign servers.

    The first is a good thing as it also prevents spammers from connecting
    to your hosting provider's mail server and forging messages from your
    domain. Some years ago the white house's mailserver did not have this
    kind of protection and allowed everyone to almost perfectly fake a mail
    from the president.

    In the latter case, if your telco does not allow connections to foreign
    smtp servers they do not provide full-featured internet access and you
    should ask them to cease and desist or change your provider.

    > So, if I understand SPF correctly (and I may not), the procedure is to list
    > the (IP) addresses of machines that may be running SMTP servers through which
    > I may ever legitimately send an email.

    Correct.

    > Now, I have no idea how many of those servers there are or what their
    > addresses are.

    Should be easy to figure out using an A query (host -t a $smtpserver).

    > UNLESS -- SPF only needs simple records (not IP addresses) like:

    You could use ptr type records.

    > And what about the reports that Microsoft's patents (pending) make the
    > whole system suspect?

    They affect Sender-ID which was therefore dropped by IETF's MARID
    working group.

    Tom 

    -- 
  T h o m a s   Z e h e t b a u e r   ( TZ251 )
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