R: [OT] How to avoid Backscatter in Sendmail
steve.freegard at fsl.com
Wed Apr 21 15:08:17 IST 2010
On 21/04/10 14:50, Marcello Anderlini wrote:
> No my system is a Linux Centos with sendmail
If the mailboxes are for local UNIX users then generating backscatter
for unknown users is impossible unless you are using something like
Cyrus (which requires a plug-in to verify users).
I've just checked and unless I'm missing something:
smf at smf-laptop:~$ host -t MX database.it
database.it mail is handled by 10 netra2.database.it.
smf at smf-laptop:~$ host netra2.database.it
netra2.database.it has address 220.127.116.11
smf at smf-laptop:~$ host 18.104.22.168.ips.backscatterer.org
Host 22.214.171.124.ips.backscatterer.org not found: 3(NXDOMAIN)
^^^ Shows that you are not listed
Also I checked:
smf at smf-laptop:~$ telnet netra2.database.it 25
Connected to netra2.database.it (126.96.36.199).
Escape character is '^]'.
220 netra.database.it ESMTP Sendmail 8.13.1/8.13.1; Wed, 21 Apr 2010
pleased to meet you
250-AUTH DIGEST-MD5 CRAM-MD5 LOGIN PLAIN
250 2.1.0 <>... Sender ok
RCPT TO:<sldjfskldjfslkdfjs at database.it>
550 5.1.1 <sldjfskldjfslkdfjs at database.it>... User unknown
221 2.0.0 netra.database.it closing connection
Connection closed by foreign host.
^^^ Shows that you are correctly rejecting unknown users at the SMTP stage.
So I can't see any problems at all.
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