From owner-freebsd-questions@FreeBSD.ORG  Mon Jun 15 08:59:27 2015
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@hub.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id EE1EF43F
 for <freebsd-questions@hub.freebsd.org>; Mon, 15 Jun 2015 08:59:27 +0000 (UTC)
 (envelope-from bc979@lafn.org)
Received: from zoom.lafn.org (zoom.lafn.org [108.92.93.123])
 by mx1.freebsd.org (Postfix) with ESMTP id CA28E842
 for <freebsd-questions@freebsd.org>; Mon, 15 Jun 2015 08:59:27 +0000 (UTC)
 (envelope-from bc979@lafn.org)
Received: from [10.0.1.2] (static-71-177-216-148.lsanca.fios.verizon.net
 [71.177.216.148]) (authenticated bits=0)
 by zoom.lafn.org (8.14.7/8.14.9) with ESMTP id t5F8pTCT032756
 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO)
 for <freebsd-questions@freebsd.org>; Mon, 15 Jun 2015 01:51:30 -0700 (PDT)
 (envelope-from bc979@lafn.org)
From: Doug Hardie <bc979@lafn.org>
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: quoted-printable
Subject: Sendmail Modification
Message-Id: <BFE727A9-33F5-4FB1-9C6D-46312AEE57AE@lafn.org>
Date: Mon, 15 Jun 2015 01:51:29 -0700
To: FreeBSD - <freebsd-questions@freebsd.org>
Mime-Version: 1.0 (Mac OS X Mail 8.2 \(2098\))
X-Mailer: Apple Mail (2.2098)
X-Virus-Scanned: clamav-milter 0.98 at zoom.lafn.org
X-Virus-Status: Clean
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.20
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions/>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 15 Jun 2015 08:59:28 -0000

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?