CentOS - Dec 2018 - Spamassassin + Postfix : delete spam mail on the server ?

Hi,

My mail server is running on CentOS 7 with Postfix, Dovecot and
Spamassassin. I get quite a lot of spam on a few accounts, and
Spamassassin does its job fine. Spam mail is identified correctly, and
it looks like there are no false positives, e. g. valid mail is never
identified as spam.

When a message is flagged as spam, the subject line is rewritten to
begin with [SPAM]. Then, a filter in Mozilla Thunderbird is setup, and
when a subject line begins with [SPAM] the message is directly sent to
Trash.

I've documented the whole configuration here:

  * https://blog.microlinux.fr/spamassassin-centos/

The problem with this setup is that spam mail is still delivered, and I
need Thunderbird's filters to weed out incoming mail. And when I'm using
my webmail (running SquirrelMail), my inbox is a tsunami of unread
[SPAM] messages.

So I'd like to go a step further and delete all messages flagged [SPAM]
directly on the server. It doesn't look like Spamassassin provides this
functionality.

Did any of you guys succeed in doing this anyway?

Cheers,

Niki


-- 
Microlinux - Solutions informatiques durables
7, place de l'?glise - 30730 Montpezat
Site : https://www.microlinux.fr
Blog : https://blog.microlinux.fr
Mail : info at microlinux.fr
T?l. : 04 66 63 10 32

On 18/12/2018 08:08, Nicolas Kovacs wrote:
> Hi,
> 
> My mail server is running on CentOS 7 with Postfix, Dovecot and
> Spamassassin. I get quite a lot of spam on a few accounts, and
> Spamassassin does its job fine. Spam mail is identified correctly, and
> it looks like there are no false positives, e. g. valid mail is never
> identified as spam.
> 
> When a message is flagged as spam, the subject line is rewritten to
> begin with [SPAM]. Then, a filter in Mozilla Thunderbird is setup, and
> when a subject line begins with [SPAM] the message is directly sent to
> Trash.
> 
> I've documented the whole configuration here:
> 
>   * https://blog.microlinux.fr/spamassassin-centos/
> 
> The problem with this setup is that spam mail is still delivered, and I
> need Thunderbird's filters to weed out incoming mail. And when I'm
using
> my webmail (running SquirrelMail), my inbox is a tsunami of unread
> [SPAM] messages.
> 
> So I'd like to go a step further and delete all messages flagged [SPAM]
> directly on the server. It doesn't look like Spamassassin provides this
> functionality.
> 
> Did any of you guys succeed in doing this anyway?
> 
> Cheers,
> 
> Niki
> 
I've used for quite some time now a combination of
postfix+SA+MailScanner for this, not delivering mails, but letting those
in a quarantine, and using Mailwatch (http frontend) to let people
release mail from the quarantine, etc ..

https://www.mailscanner.info/
https://mailwatch.org/

And the ansible role that I initially used for this on CentOS 7 :
https://github.com/arrfab/ansible-role-mail-gateway

Cheers,

-- 
Fabian Arrotin
The CentOS Project | https://www.centos.org
gpg key: 56BEC54E | twitter: @arrfab

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> The problem with this setup is that spam mail is still delivered, and I
> need Thunderbird's filters to weed out incoming mail. And when I'm
using
> my webmail (running SquirrelMail), my inbox is a tsunami of unread
> [SPAM] messages.
> 
> So I'd like to go a step further and delete all messages flagged [SPAM]
> directly on the server. It doesn't look like Spamassassin provides this
> functionality.
> 
Spamassassin just tags things, it doesn't interact with the final mail
delivery. What you need is some form of server-side filtering

My (limited) expertise in MTAs is with Exim and that has an extensive
filter syntax that goes in the user's .forward file - I use that to
pre-filter my mail before the MUA sees it.  From my .forward file:

   if
       $h_X-Spam-Flag: contains "Yes"
   then
       save  Maildir/.spam/
       finish
   endif

   if $header_subject: contains "[CentOS" then
   	save Maildir/.CentOS/
       finish
   endif

If you don't want to use a different MTA, then the classic way of doing
server side filtering is using procmail.  I'm certain there will be
lots of HowTos out there on how to set it all up with Postfix.

Finally, I would be quite surprised if there is no built-in filtering
of some form with Postfix, but from the articles I've just been looking
at it doesn't seem to be a simple process.

P.

Hi,

Procmail, it can move messages around based on many rules.
Use something like this in postfix main.cf:
mailbox_command = /usr/bin/procmail-wrapper -o -a $DOMAIN -d $LOGNAME

And something like this in /etc/procmailrc or $HOME/.procmailrc

SPAMDIR=$HOME/Maildir/.Spam/
:0fw
| /usr/bin/spamc
:0
* ^X-Spam-Status: Yes
$SPAMDIR
DEFAULT=$HOME/Maildir/
ORGMAIL=$HOME/Maildir/
DROPPRIVS=yes


HTH

--
Sent from the Delta quadrant using Borg technology!

Nux!
www.nux.ro

----- Original Message -----
> From: "Nicolas Kovacs" <info at microlinux.fr>
> To: "CentOS mailing list" <centos at centos.org>
> Cc: "scholae >> AA Tous les salari?s" <scholae at
lists.tuxfamily.org>
> Sent: Tuesday, 18 December, 2018 07:08:55
> Subject: [CentOS] Spamassassin + Postfix : delete spam mail on the server ?
> Hi,
> 
> My mail server is running on CentOS 7 with Postfix, Dovecot and
> Spamassassin. I get quite a lot of spam on a few accounts, and
> Spamassassin does its job fine. Spam mail is identified correctly, and
> it looks like there are no false positives, e. g. valid mail is never
> identified as spam.
> 
> When a message is flagged as spam, the subject line is rewritten to
> begin with [SPAM]. Then, a filter in Mozilla Thunderbird is setup, and
> when a subject line begins with [SPAM] the message is directly sent to
> Trash.
> 
> I've documented the whole configuration here:
> 
>  * https://blog.microlinux.fr/spamassassin-centos/
> 
> The problem with this setup is that spam mail is still delivered, and I
> need Thunderbird's filters to weed out incoming mail. And when I'm
using
> my webmail (running SquirrelMail), my inbox is a tsunami of unread
> [SPAM] messages.
> 
> So I'd like to go a step further and delete all messages flagged [SPAM]
> directly on the server. It doesn't look like Spamassassin provides this
> functionality.
> 
> Did any of you guys succeed in doing this anyway?
> 
> Cheers,
> 
> Niki
> 
> 
> --
> Microlinux - Solutions informatiques durables
> 7, place de l'?glise - 30730 Montpezat
> Site : https://www.microlinux.fr
> Blog : https://blog.microlinux.fr
> Mail : info at microlinux.fr
> T?l. : 04 66 63 10 32
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos

At Tue, 18 Dec 2018 08:08:55 +0100 CentOS mailing list <centos at
centos.org> wrote:
> 
> 
> Hi,
> 
> My mail server is running on CentOS 7 with Postfix, Dovecot and
> Spamassassin. I get quite a lot of spam on a few accounts, and
> Spamassassin does its job fine. Spam mail is identified correctly, and
> it looks like there are no false positives, e. g. valid mail is never
> identified as spam.
> 
> When a message is flagged as spam, the subject line is rewritten to
> begin with [SPAM]. Then, a filter in Mozilla Thunderbird is setup, and
> when a subject line begins with [SPAM] the message is directly sent to
> Trash.
You have two options:

If you have mimedefang installed and using it run spamassassin over all 
incoming messages, you can change mimedefang's default spamassassin filter 
interface from merely tagging messages to actually rejecting them -- 
mimedefang can return a code to tell Postfix to boot the spam message with a 
5xx status. 

Or you can have a recipe in .procmailrc to file (or otherwise) messages tagged 
as spam.

(Another thing you can do is configure Postfix's access and client.cidr
files
to refuse to even talk to various hosts that are known spam sources -- pretty
much all of China, Vietnam, Russia (and former USSR countries), and Brazil as
well as all of the "silly" TLDs: .science, .stream, .store, .webcam, 
.acountant, .life, .today, and many more.)
> 
> I've documented the whole configuration here:
> 
>   * https://blog.microlinux.fr/spamassassin-centos/
> 
> The problem with this setup is that spam mail is still delivered, and I
> need Thunderbird's filters to weed out incoming mail. And when I'm
using
> my webmail (running SquirrelMail), my inbox is a tsunami of unread
> [SPAM] messages.
> 
> So I'd like to go a step further and delete all messages flagged [SPAM]
> directly on the server. It doesn't look like Spamassassin provides this
> functionality.
> 
> Did any of you guys succeed in doing this anyway?
> 
> Cheers,
> 
> Niki
> 
> 
-- 
Robert Heller             -- 978-544-6933
Deepwoods Software        -- Custom Software Services
http://www.deepsoft.com/  -- Linux Administration Services
heller at deepsoft.com       -- Webhosting Services

On 12/18/18 4:02 AM, Nux! wrote:
> Hi,
> 
<snip>
> 
> HTH
> 
> --
> Sent from the Delta quadrant using Borg technology!
> 
I am just curios how much do they pay you for advertising them in all 
your posts to this mail list. Or what is different - non-monetary - 
incentive you have for doing so?

Valeri
> Nux!
> www.nux.ro
> 
<snip>

-- 
++++++++++++++++++++++++++++++++++++++++
Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
++++++++++++++++++++++++++++++++++++++++

On 12/18/18 3:34 AM, Fabian Arrotin wrote:
> On 18/12/2018 08:08, Nicolas Kovacs wrote:
>> Hi,
>>
>> My mail server is running on CentOS 7 with Postfix, Dovecot and
>> Spamassassin. I get quite a lot of spam on a few accounts, and
>> Spamassassin does its job fine. Spam mail is identified correctly, and
>> it looks like there are no false positives, e. g. valid mail is never
>> identified as spam.
>>
>> When a message is flagged as spam, the subject line is rewritten to
>> begin with [SPAM]. Then, a filter in Mozilla Thunderbird is setup, and
>> when a subject line begins with [SPAM] the message is directly sent to
>> Trash.
>>
>> I've documented the whole configuration here:
>>
>>    * https://blog.microlinux.fr/spamassassin-centos/
>>
>> The problem with this setup is that spam mail is still delivered, and I
>> need Thunderbird's filters to weed out incoming mail. And when
I'm using
>> my webmail (running SquirrelMail), my inbox is a tsunami of unread
>> [SPAM] messages.
>>
>> So I'd like to go a step further and delete all messages flagged
[SPAM]
>> directly on the server. It doesn't look like Spamassassin provides
this
>> functionality.
>>
>> Did any of you guys succeed in doing this anyway?
>>
>> Cheers,
>>
>> Niki
>>
> 
> I've used for quite some time now a combination of
> postfix+SA+MailScanner for this, not delivering mails, but letting those
> in a quarantine, and using Mailwatch (http frontend) to let people
> release mail from the quarantine, etc ..
Thanks, Fabian. I was looking for something like that for long time. I 
was using the above under amavisd-new. And as I didn't find GUI 
front-end ;-( I ended up using maia mailguard. By that point I switched 
servers to FreeBSD, and there is FreeBSD maia port which is being 
actively maintained by brilliant person, so that may be the best source 
to get maia from, not the main maia website.

Thanks again, it looks like mailwatch does everything I needed (and 
found in maia): per user white/blacklists, other individual setting, 
quarantene release, etc.

Valeri
> 
> https://www.mailscanner.info/
> https://mailwatch.org/
> 
> And the ansible role that I initially used for this on CentOS 7 :
> https://github.com/arrfab/ansible-role-mail-gateway
> 
> Cheers,
> 
> 
> _______________________________________________
> CentOS mailing list
> CentOS at centos.org
> https://lists.centos.org/mailman/listinfo/centos
> 
-- 
++++++++++++++++++++++++++++++++++++++++
Valeri Galtsev
Sr System Administrator
Department of Astronomy and Astrophysics
Kavli Institute for Cosmological Physics
University of Chicago
Phone: 773-702-4247
++++++++++++++++++++++++++++++++++++++++

Am 18.12.2018 um 08:08 schrieb Nicolas Kovacs:
> The problem with this setup is that spam mail is still delivered, and I
> need Thunderbird's filters to weed out incoming mail. And when I'm
using
> my webmail (running SquirrelMail), my inbox is a tsunami of unread
> [SPAM] messages.
> 
> So I'd like to go a step further and delete all messages flagged [SPAM]
> directly on the server. It doesn't look like Spamassassin provides this
> functionality.
What's the point of delivering identified SPAM and then deleting it? 
Reject SPAM at SMTP level on your MTA. Easy to do with amavisd-new in a 
smtp proxy setup with Postfix.

Alexander

> Am 18.12.2018 um 08:08 schrieb Nicolas Kovacs:
>> The problem with this setup is that spam mail is still delivered, and I
>> need Thunderbird's filters to weed out incoming mail. And when
I'm using
>> my webmail (running SquirrelMail), my inbox is a tsunami of unread
>> [SPAM] messages.
>>
>> So I'd like to go a step further and delete all messages flagged
[SPAM]
>> directly on the server. It doesn't look like Spamassassin provides
this
>> functionality.
>
> What's the point of delivering identified SPAM and then deleting it?
> Reject SPAM at SMTP level on your MTA. Easy to do with amavisd-new in a
> smtp proxy setup with Postfix.
There are good reasons to not reject detected SPAM because your SPAM
filter could be wrong and you reject legitimate mail.

For businesses depending on email communication that's a no go, because
you may lose customers that way.

Regards,
Simon