Ident based rejecting (sendmail)

Abstract

The document describes how to make sendmail reject email messages based on information received by ident queries (RFC 1413).

It can be used to block access from some open proxies.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
THE AUTHOR NAME MUST BE QUOTED IN ANY WORK DERIVATED FROM THE WORK.

Install

Copy provided identblock.m4 file (the gpg signature into cf/feature directory.

Add the following lines to *.mc file you use to generate sendmail.cf

FEATURE(`identblock')dnl
LOCAL_CONFIG
C{BadIdentUsers}squid CacheFlowServer

Make sure there are TABs (\t) between RHSes and LHSes in the above line (Right/Left Hand Side)
Modify ident names to be blocked listed in C{BadIdentUsers} line to fit your requirements

Tests

Add the following rule set to your *.mc file

LOCAL_RULESETS
Stest
R$* $$| $*      $: $1 $| $2

after that you can use commands given below for testing the feature:

sendmail -C sendmail-test.cf -bt <<END
.D_IDENT:squid@localhost [1.2.3.4]
test,check_relay x.com $| 1.2.3.4
END

Original Posting

The posting
Subject: Re: block by sender ident=squid
Date: 2002-05-02
Newsgroups: comp.mail.sendmail
Message-ID: <3CD18E66.9C1F7A0B@bigfoot.com>

Ident based rejecting (sendmail)

Abstract

Install

Tests

Additional

Original Posting