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Date:      Mon, 15 Jun 2015 01:51:29 -0700
From:      Doug Hardie <bc979@lafn.org>
To:        FreeBSD - <freebsd-questions@freebsd.org>
Subject:   Sendmail Modification
Message-ID:  <BFE727A9-33F5-4FB1-9C6D-46312AEE57AE@lafn.org>

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I need to modify sendmail such that when a SMTP-AUTH request fails, =
sendmail drops the connection.  I am constantly being hit by password =
guessing attempts.  My first thought was to introduce a 1 or 2 minute =
delay after an authentication failure.  However, I suspect the attackers =
would just open a new connection and leave me with bunches of =
connections waiting to time out.  Hence the need to drop the connection.

Looking through the code it appears there are 2 places in srvrsmtp.c =
where the SASL return code is not SASL_OK or SASL_CONT.  An "AUTH =
failure=E2=80=9D is logged in both those instances.  I believe that an =
exit right after the RESET_SASLCONN would do what I need.  Does this =
appear to be the right place?




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