[OT] How to avoid Backscatter in Sendmail

[Marcello Anderlini]

I beg your pardon but for this OT but I'm desperate, my system is
blacklisted by Backscatterer.org and I'm trying to configure it to avoid
backscatter.
I'm following what suggest here:
http://elqui.dcsc.utfsm.cl/util/email/backscatter.html

I'm using sendmail-8.13.1-3.3.el4. on a CentOS release 4.8.
I configured my access file to reject unknown recipients but my system still
sends an email instead of rejecting it at smtp initial transaction.

I would be very grateful for any kind of help anyone could give me.

Best regards


This is my sendmail.mc

divert(-1)
dnl This is the sendmail macro config file. If you make changes to this
file,
dnl you need the sendmail-cf rpm installed and then have to generate a
dnl new /etc/sendmail.cf by running the following command:
dnl
dnl        m4 /etc/mail/sendmail.mc > /etc/sendmail.cf
dnl
include(`/usr/share/sendmail-cf/m4/cf.m4')
VERSIONID(`linux setup for Red Hat Linux')dnl
OSTYPE(`linux')
define(`confDEF_USER_ID',``8:12'')dnl
undefine(`UUCP_RELAY')dnl
undefine(`BITNET_RELAY')dnl
define(`confTO_CONNECT', `1m')dnl
define(`confTRY_NULL_MX_LIST',true)dnl
define(`confDONT_PROBE_INTERFACES',true)dnl
define(`PROCMAIL_MAILER_PATH',`/usr/bin/procmail')dnl
define(`ALIAS_FILE', `/etc/aliases')dnl
define(`confCW_FILE', `/etc/mail/sendmail.cw')dnl
dnl define(`STATUS_FILE', `/etc/mail/statistics')dnl
define(`UUCP_MAILER_MAX', `2000000')dnl
define(`confUSERDB_SPEC', `/etc/mail/userdb.db')dnl
define(`confPRIVACY_FLAGS', `authwarnings,novrfy,noexpn,restrictqrun')dnl
define(`confAUTH_OPTIONS', `A')dnl
TRUST_AUTH_MECH(`DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
define(`confAUTH_MECHANISMS', `DIGEST-MD5 CRAM-MD5 LOGIN PLAIN')dnl
define(`confBAD_RCPT_THROTTLE',`2')dnl
dnl define(`confTO_QUEUEWARN', `4h')dnl
dnl define(`confTO_QUEUERETURN', `5d')dnl
dnl define(`confQUEUE_LA', `12')dnl
dnl define(`confREFUSE_LA', `18')dnl
dnl FEATURE(delay_checks)dnl
FEATURE(`no_default_msa',`dnl')dnl
FEATURE(`smrsh',`/usr/sbin/smrsh')dnl
FEATURE(`mailertable',`hash -o /etc/mail/mailertable.db')dnl
FEATURE(redirect)dnl
FEATURE(always_add_domain)dnl
FEATURE(use_cw_file)dnl
FEATURE(use_ct_file)dnl
FEATURE(local_procmail,`',`procmail -t -Y -a $h -d $u')dnl
FEATURE(`access_db',`hash -T<TMPF> -o /etc/mail/access.db')dnl
FEATURE(`blacklist_recipients')dnl
FEATURE(`virtusertable',`hash -o /etc/mail/virtusertable.db')dnl
FEATURE(`enhdnsbl', `bl.spamcop.net', `"553 rejected - see
http://spamcop.net/bl.shtml?"$&{client_addr}', `')dnl
FEATURE(`enhdnsbl', `cbl.abuseat.org', `"553 rejected - see
http://cbl.abuseat.org/lookup.cgi?"$&{client_addr}', `')dnl
FEATURE(`enhdnsbl', `sbl-xbl.spamhaus.org', `"553 rejected - see
http://www.spamhaus.org/query/bl?"$&{client_addr}', `')dnl
FEATURE(`enhdnsbl', `clients.blocked.rbl', `"553 rejected - see
http://www.database.it/bl.asp?"$&{client_addr}', `')dnl
FEATURE(`enhdnsbl', `hosts.blocked.rbl', `"553 rejected - see
http://www.database.itt/bl.asp?"$&{client_addr}', `')dnl
EXPOSED_USER(`root')dnl
dnl This changes sendmail to only listen on the loopback device 127.0.0.1
dnl and not on any other network devices. Comment this out if you want
dnl to accept email over the network.
dnl DAEMON_OPTIONS(`Port=smtp,Addr=127.0.0.1, Name=MTA')
dnl NOTE: binding both IPv4 and IPv6 daemon to the same port requires
dnl       a kernel patch
dnl DAEMON_OPTIONS(`port=smtp,Addr=::1, Name=MTA-v6, Family=inet6')
dnl We strongly recommend to comment this one out if you want to protect
dnl yourself from spam. However, the laptop and users on computers that do
dnl not have 24x7 DNS do need this.
dnl FEATURE(`accept_unresolvable_domains')dnl
FEATURE(`relay_based_on_MX')dnl
MAILER(smtp)dnl
MAILER(procmail)dnl
Cwlocalhost.localdomain



Dr. Marcello Anderlini
m.anderlini at database.it
---------------------------------------------
Database Informatica S.r.l.
Microsoft Certified Partner
Tel.  +39059775070
Fax. +39059779545
http://www.database.it
--------------------------------------------- 


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