smtpd_helo_restrictions = ..., reject_unknown_helo_hostname occasionally rejects mail I care about, how to handle?

Posted by lkraav on Server Fault See other posts from Server Fault or by lkraav
Published on 2013-01-06T18:56:08Z Indexed on 2013/11/10 22:02 UTC
Read the original article Hit count: 318

Filed under:

linux

|

postfix

|

administration

|

spam-prevention

I have configured my postfix as follows:

smtpd_helo_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unknown_helo_hostname

This is working well because most spambots don't seem to have correct reverse lookups. But every once in a while I run into mail I care about getting reject, because the mail source server admin doesn't care about configuring his server correctly.

For example here the server introduces itself as "srv1.xbmc.org" which has no DNS record and fails my basic check.

Jan  6 04:42:36 mail postfix/smtpd[660]: connect from xbmc.org[205.251.128.242]
Jan  6 04:42:37 mail postfix/smtpd[660]: NOQUEUE: reject: RCPT from xbmc.org[205.251.128.242]: 450 4.7.1 <srv1.xbmc.org>: Helo command rejected: Host not found; from=<[email protected]> to=<[email protected]> proto=ESMTP helo=<srv1.xbmc.org>

I have tried to contact the server admin several times, but there is no response. What is the optimal way to handle this from my side? Is adding these "special" hosts to mynetworks = my only option? Is perhaps my whole smtpd_helo_restrictions setup wrong in some significant way?

© Server Fault or respective owner

Related posts about linux

apt-get install and update fail

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I've got a problem with apt-get update and apt-get install ... commands . every time update or installing fails and errors are : Get:1 http://dl.google.com stable Release.gpg [198B] Ign http://dl.google.com/linux/chrome/deb/ stable/main Translation-en_US Get:2 http://dl… >>> More
kernel module compiling error

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
sh@ubuntu:/home/ccpp/helloworld$ make gcc-4.6 -O2 -DMODULE -D_KERNEL_ -W -Wall -Wstrict-prototypes -Wmissing-prototypes -isystem /lib/modules/`uname -r`/build/include -c -o hello-1.o hello-1.c hello-1.c:4:0: warning: "MODULE" redefined [enabled by default] <command-line>:0:0: note: this is… >>> More
Build-Essentials installation failing

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I am having trouble accessing the several critical header files that show to be a part of the build process. The "Ubuntu Software Center" shows "Build Essentials" as installed: Next I did the following two commands, which did not improve the problem: ~$ sudo apt-get install build-essential [sudo]… >>> More
Updating Debian kernel

as seen on Super User - Search for 'Super User'
I'm trying to update my Debian machine to 2.6.32-46 (which is the new stable). However, after doing apt-get update my apt-cache search linux-image shows me: linux-headers-2.6.32-5-486 - Header files for Linux 2.6.32-5-486 linux-headers-2.6.32-5-686-bigmem - Header files for Linux 2.6.32-5-686-bigmem linux-headers-2… >>> More
Serial connection over a single USB cable (Windows to linux, or linux to linux)

as seen on Server Fault - Search for 'Server Fault'
I'm helping out with a project for an embedded device that only has USB and no serial. This device is running Linux. These days, when we need to connect to a serial port on a device we typically use a USB to serial adapter (on something like a phone system or a load balancing device, etc). I would… >>> More

Related posts about postfix

postfix: Temporary lookup failure

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
I have followed the tutorials step by step for installing and configuring postfix https://help.ubuntu.com/community/Postfix https://help.ubuntu.com/community/PostfixBasicSetupHowto I am trying to test the services to whether Temporary lookup failure error telnet localhost 25 250 2.1.0 Ok rcpt to:… >>> More
postfix with mailman

as seen on Server Fault - Search for 'Server Fault'
What should happen is that [email protected] should be delivered to that users inbox on localhost, user@localhost. Thunderbird works fine at reading user@localhost. I'm just using a small portion of postfix-dovecot with Ubuntu mailman. How can I get postfix to recognize the FQDN and deliver… >>> More
saslauthd + PostFix producing password verification and authentication errors

as seen on Server Fault - Search for 'Server Fault'
So I'm trying to setup PostFix while using SASL (Cyrus variety preferred, I was using dovecot earlier but I'm switching from dovecot to courier so I want to use cyrus instead of dovecot) but I seem to be having issues. Here are the errors I'm receiving: ==> mail.log <== Aug 10 05:11:49 crazyinsanoman… >>> More
centos postfix send email problem

as seen on Server Fault - Search for 'Server Fault'
Hello. I have a big problem with postfix. I can receive mail in webmin and outlook but I can't send (only on local I can - user to user). Dovecot is working just fine. Sendmail is disable. Please help me. postfix -n postfix: invalid option -- n postfix: fatal: usage: postfix [-c config_dir] [-Dv]… >>> More
Migrating users and mailboxes from postfix / Maildir to Postfix with Mysql backend

as seen on Server Fault - Search for 'Server Fault'
So I've got 60 or so users on a hand rolled postfix installation on openbsd and I'd like to move their mailboxes to our new mail server running iRedMail (postfix, vmail/mysql back end) Does anyone know of a good way to do this? Preferably a script I can run to keep syncing the users mailboxes as… >>> More