Re: [exim] Prevent / refuse Mail from : <> null sender in ex…

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Author: Odhiambo Washington
Date:  
To: mueller
CC: exim users
Subject: Re: [exim] Prevent / refuse Mail from : <> null sender in exim
On 8 November 2016 at 10:50, Mueller <mueller@???> wrote:

> Hello to all,
>
> My exim version:
>
> exim -bV
> Exim version 4.72 #1 built 10-Oct-2014 09:23:33
> Copyright (c) University of Cambridge, 1995 - 2007
> Berkeley DB: Berkeley DB 4.7.25: (September 9, 2013)
> Support for: crypteq iconv() IPv6 PAM Perl Expand_dlfunc TCPwrappers
> OpenSSL
> Content_Scanning DKIM Old_Demime
> Lookups (built-in): lsearch wildlsearch nwildlsearch iplsearch cdb dbm
> dbmnz
> dnsdb dsearch ldap ldapdn ldapm nis nis0 nisplus passwd sqlite
> Authenticators: cram_md5 cyrus_sasl dovecot plaintext spa
> Routers: accept dnslookup ipliteral manualroute queryprogram redirect
> Transports: appendfile/maildir/mailstore/mbx autoreply lmtp pipe smtp
> Fixed never_users: 0
> Size of off_t: 8
> OpenSSL compile-time version: OpenSSL 1.0.1e-fips 11 Feb 2013
> OpenSSL runtime version: OpenSSL 1.0.1e-fips 11 Feb 2013
> Configuration file is /etc/exim/exim.conf
>
>
>
>
> we have a problem with null sender mails. The mails getting started with
> spams comming in, and just result in relay access denied:
>
> Message 1c2Zcm-0007Qi-L7 has been frozen (message created with -f <>).
> The sender is <>.
>
> The following address(es) have yet to be delivered:
> schulzanne@??? <schulzanne@???>: SMTP error from remote
> mail
> server after RCPT TO:<schulzanne@???>: host mail.tropenklinik.de
> [213.185.88.41]: 554 5.7.1 <schulzanne@???>: Relay access denied
>
> How can I discard this messages or set up exim to refuse any null sender
> (senders= : )!?? So no one can send with , mail from :<>.
>
> Greetings
> Daniel
>
>

My suggestion is that you work harder at making sure your spam filters work
(https://github.com/Exim/exim/wiki/SpamFiltering).
The null sender is so legit because it's used for sending legit bounces.
Maybe you can share your whole Exim configuration for the experts here to
advise you on where the loophole is.
For starters, why don't you apply Lena's configuration to yours. They
really helped many. (http://lena.kiev.ua/Lena-eximconf-run.txt)


--
Best regards,
Odhiambo WASHINGTON,
Nairobi,KE
+254 7 3200 0004/+254 7 2274 3223
"Oh, the cruft."