Bijayant Kumar
--- On Tue, 6/1/09, DJ Lucas <d...@lucasit.com> wrote:
> From: DJ Lucas <d...@lucasit.com>
> Subject: Re: Blocking Spam
> To: "postfix" <postfix-users@postfix.org>
> Date: Tuesday, 6 January, 2009, 6:34 AM
> bijayant kumar wrote:
> > Hello list,
> >
> > Now a days we are getting lots of spam emails from our
> own email-ids. I want to block this. I have tried to block
> senders domains which are local and not doing smtp-auth.
> While implementing I come across a new problem like, when I
> rejected a spam coming from my own email-id from another
> spam server, I got Bounce-Notification message also. As the
> account(my email id) is local, it entitled to get the Bounce
> Notification. How to overcome this issue? Any suggestion or
> reading.
> >
> >
> <SNIP>
> > I am trying to reject the mails which is coming from
> a...@abc.com without smtp-authentication. It is being
> rejected but the bounce message is getting delivered to
> a...@abc.com as this domain and email is local. This is the
> problem.
> > Bijayant Kumar
> >
> What is the source of the NDR (show headers if it is not
> you) and
> why/how was the original message rejected (logs)?
>
I think I was not clear on my question. As we all know spammers uses the from
address as our own email address and spamming like anything, right. In those
emails from address and To address both are same. So, I tried to block those
spams which are local and not doing smtp-authentication. I have tried to
simulate the scenario on my local testing environments.
I have created a test domain kavach.com and a user bijay...@kavach.com. I have
telneted on one another postfix installation and tried to send emails from
bijay...@kavach.com to bijay...@kavach.com. What I observed the email is
rejected as desired because it has sent without the smtp-authentication. But
bijay...@kavach.com also received the bounce-notification message i.e
undelivered mail returned to sender.
Postconf -n on test machine
mynetworks = 127.0.0.0/8
mynetworks_style = subnet
myorigin = $mydomain
newaliases_path = /usr/bin/newaliases
queue_directory = /var/spool/postfix
readme_directory = /usr/share/doc/postfix-2.5.5/readme
sample_directory = /etc/postfix
sendmail_path = /usr/sbin/sendmail
setgid_group = postdrop
smtpd_recipient_restrictions =
permit_mynetworks
permit_sasl_authenticated
reject_unauth_destination
check_sender_access hash:/etc/postfix/access_sender
smtpd_sasl_auth_enable = yes
smtpd_sasl_security_options = noanonymous
unknown_local_recipient_reject_code = 550
cat /etc/postfix/access_sender
kavach.com REJECT
.kavach.com REJECT
Mail-Log
I sent a mail from another postfix installation
postfix/smtpd[14415]: connect from unknown[192.168.99.22]
postfix/smtpd[14415]: NOQUEUE: reject: RCPT from unknown[192.168.99.22]: 554
5.7.1 <bijay...@kavach.com>: Sender address rejected: Access denied;
from=<bijay...@kavach.com> to=<bijay...@kavach.com> proto=ESMTP
helo=<test1.localdomain>
postfix/smtpd[14415]: disconnect from unknown[192.168.99.22]
postfix/smtpd[14415]: connect from unknown[192.168.99.22]
postfix/smtpd[14415]: 4C8ED7F68D: client=unknown[192.168.99.22]
postfix/cleanup[14421]: 4C8ED7F68D:
message-id=<20090106054312.37623df...@test1.localdomain>
postfix/qmgr[14308]: 4C8ED7F68D: from=<>, size=2520, nrcpt=1 (queue active)
postfix/smtpd[14415]: disconnect from unknown[192.168.99.22]
postfix/virtual[14422]: 4C8ED7F68D: to=<bijay...@kavach.com>, relay=virtual,
delay=0.05, delays=0.03/0.01/0/0.01, dsn=2.0.0, status=sent (delivered to
maildir)
Hope I am clear this time.
> -- DJ Lucas
>
>
> --
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