Postfix - antispam and relay package

Bismarck

Hoping someone can help me out with this type of spam I just cannot figure out how to stop.

Hi FlashPan, this can be done easily with postfix:

1. Setup a proper RBL server List, you can combine as many as you wish if you set a higher RBL threshold. Which could block dynamic ips by default also = 106.247.219.88.rev.sfr.net [88.219.247.106])

2. Postfix > antispam > Header add this:

*/^Received:.rev.sfr.net / REJECT #will reject ALL dynamic ips from *rev.sfr.net

/^From:.*@bt.com/ REJECT #will reject all mail from someone@bt.com

/^Subject:.*(Important - BT Digital File):/ REJECT #will reject all mail with subject Important - BT Digital File

4. Subscribe additional rules for MailScanner/Spamassassin (google it)

https://wiki.apache.org/spamassassin/CustomRulesets

5. You also can write your own rules for MailScanner/Spamassassin:

https://wiki.apache.org/spamassassin/WritingRules

place your custom rules in /var/db/spamassassin/3.004000/70_myrules.cf and restart MailScanner. After adding new rules always check your mail log for errors or false positives! But Postfix is easier to handle, so start there.

Using pfblocker for spam prevention is a BAD idea, because you will miss if a legit email gets blocked etc….

Good luck!

biggsy

@FlashPan:

Subject: Important - BT Digital File

Hmmm, smells like phish. Hope your users are clued up about that stuff.

An example of what Bismarck is recommending in point 1.

Paste this into your Postfix > Antispam > RBL Server list

zen.spamhaus.org*2, bl.spamcop.net, 0spam.fusionzero.com

and set your RBL threshold to 2.

spamhaus catches most of this sort of stuff on my system, hence the *2 to breach the threshold.

88.219.247.106 is definitely listed.

biggsy

@pyrodex:

Any chance of getting this to work in 2.2?

Are you talking about Postfix forwarder on 2.2? I have had some problems with that.

Installing postfix on 2.2 (with a config restored from 2.1.5) I'm getting the following:

postfix/postfix-script[56365]: fatal: no Postfix daemon directory /usr/local/libexec/postfix!

and


php-fpm[7873]: /pkg_mgr_install.php: The command '/usr/local/sbin/postfix reload' returned exit code '1', the output was 'cd: /usr/local/libexec/postfix: No such file or directory'
php-fpm[7873]: /pkg_mgr_install.php: The command '/usr/local/sbin/postfix reload' returned exit code '1', the output was 'cd: /usr/local/libexec/postfix: No such file or directory'

Then the following repeats about 5 or 6 times:

php-fpm[8074]: /pkg_edit.php: The command '/usr/local/sbin/postfix reload' returned exit code '1', the output was 'cd: /usr/local/libexec/postfix: No such file or directory'
php-fpm[8074]: /pkg_edit.php: The command '/usr/local/sbin/postfix reload' returned exit code '1', the output was 'cd: /usr/local/libexec/postfix: No such file or directory'

All this could be due to the restored config but I don't know.

FlashPan

Thanks Bismark and biggsy,

I do have zen.spamhaus.org, bl.spamcop.net, dnsbl.sorbs.net set in my RBL list and the threshold is set to 2 already. These options have been set for months. On my firewall I'm set the automatic nat outbound rule generation so none of the rbl servers should be blocked to interogate.

Postfix is set the listen on LAN, WAN and loopback (quite a while back I only had Lan or Wan selected - if I remember correctly I think a version upgrade stop mail flowing through and only using all 3 got it working again).

Access Lists > Header:

/^Subject:/ WARN
/^From:/ HOLD
/^To:.*@MyDomain.co.uk/ HOLD

Antispam > Header verifiction: set to basic as when set to string alot of legit emails do not make it through.

Antispam > After greeting tests: all selected

In the Mailscanner app under AntiSpam > Spamchecks the only element I have selected is "Spam Checks (yes)" Nothing else is selected or have a value entered. Could that be causing some sort of clash?

Mailscanner > AntiSpam > Spam Assassin > Features: All is selected except for Include Binary Attachments and Wait during bayes rebuild

Am still at a loss :)

One other thing I have noticed is that with the Postfix widget I only see values for Sent, nothing for Rejected etc. - actually I have never seen anything except for Sent.

Emails are being rejected as when I use the Search mail feature I can see entries like this:

Sep 26 10:12:00 wing@cybercatinc.com steve@XXXX.co.uk reject
Sep 26 09:22:16 tejedas@embarq.com steve@XXXX.co.uk reject
Sep 26 09:22:16 tejedas@embarq.com j6g05dt3po6rorq@XXXX.co.uk reject

(the top 2 recipients are valid the 3rd recipient does not exist)

Apologies now, as before I did not give much detail on my setup and now I could be overloading with all the wrong info. :P

Cheers again all and thanks once again for your help.

Bismarck

First in Search Mail > Message Fields: mark all and search again, this will show you much more information. Or even better you login via putty/ssh and watch the logs live:

tail -f /var/log/maillog

Access Lists > Header:
/^Subject:/ WARN
/^From:/ HOLD
/^To:.*@MyDomain.co.uk/ HOLD

scratch that, you have just c&p the example stuff there, this would be a valid list:

#Remove sensitive information from email headers
/^Received: from MTA.LOCAL*/ IGNORE
/^Received:.*with ESMTPS/ IGNORE
/^X-Originating-IP:/ IGNORE
/^User-Agent:/ IGNORE
# SPAM
/^Received:.*rev.sfr.net / REJECT 
/^From:.*@bt.com/ REJECT
/^Subject:.*(Important - BT Digital File):/ REJECT 
# HAM
/^From:.*@XXXX.co.uk / OK

Antispam > After greeting tests: all selected

You may take this into account. (thanks biggsy)

Emails are being rejected as when I use the Search mail feature I can see entries like this:
Sep 26 10:12:00 wing@cybercatinc.com steve@XXXX.co.uk reject
Sep 26 09:22:16 tejedas@embarq.com steve@XXXX.co.uk reject
Sep 26 09:22:16 tejedas@embarq.com j6g05dt3po6rorq@XXXX.co.uk reject
(the top 2 recipients are valid the 3rd recipient does not exist)

Postfix > Access Lists > MyNetworks

Your IPs should be listed here, like:

192.168.0.7 # internal mailhost
192.168.0.1 # pfs lan
127.0.0.1   # pfs loopback

and enable Postfix > Recipients > AD etc..

Cheers! ;)

FlashPan

Thanks for all the info Bismarck. At the moment I'm not using the options uner #SPAM as I'm still; liking to get this tuff generally blocked without manual intervention…great info though for me in the future.

Am not sure why I would want to whitelist google servers? Surely that is only going to effect email coming in from google/gmail and nothing else?

I've added my ip's under Postfix > Access Lists > MyNetworks

Have been sending through some test spam/virus emials but it look like my logs have now randomly corrupted I think as when I search for anything the results are blank or give something starting with Warning: sqlite_query(): no such column: mail_status.info in /usr/local/www/postfix.php on line 606 Warning:

For Postfix > Recipients I've set Custom Valid recipients as I've not installed the p5-perl-ldap package yet.

Cheers again :D

yaboc

my postfix service doesn't stop from the services page and even when i disable the forwarder and rebbot pfsense it seems to be running. im on the current version (pf + package). any ideas why? can i kill it from cli?

jaredadams

Can someone enlighten me as to which setting(s) in the configuration causes this check?

NOQUEUE: reject: RCPT from unknown[X.X.X.X]: 550 5.7.1 Client host rejected: cannot find your hostname, [X.X.X.x]; from= email@domain.comto= email@mycompany.comproto=ESMTP helo=<[X.X.X.X]>/email@mycompany.com /email@domain.com

Bismarck

@jaredadams:

Can someone enlighten me as to which setting(s) in the configuration causes this check?

NOQUEUE: reject: RCPT from unknown[X.X.X.X]: 550 5.7.1 Client host rejected: cannot find your hostname, [X.X.X.x]; from= email@domain.comto= email@mycompany.comproto=ESMTP helo=<[X.X.X.X]>/email@mycompany.com /email@domain.com

Postfix > Antispam

Helo Hostname

Default: Checked

Reject unknow helo hostname during smtp communication.

FlashPan

Hi,

Well after some reinstall (well many) and different configs I think I've mainly got this working to block spam (mainly).

I found this website http://www.crynwr.com/spam/ and from here you can send yourself test emails which should trigger a block etc and then this site will email you the conversation/outcome.

Sadly though I still seem to have a couple of issues . My widget still does not show up anything but the Sent stats. In Search Mail, No Queue, I can see emails being rejected (eg sent to a non existant emails address). Ideas anyone?

I think I've found another issue as well. I read this on another forum but I think it may have been quite old so not sure if still valid and of course I cannot find the page again as I did not save it.

Anyhow below you will see an email header that came into to me to day. Go through Postfix and Mailsanner with no flags.

I think I read it correctly but postfix cannot block email if it passes through or relays through multiple email servers.

Anyone seen or aware of this type of thing?

As always of tip my cap to you call and thank you very much for your help past, present and future :)

Cheers

Received: from xxx.xxx.co.uk (192.168.100.4) by xxx.xxx.corp
(192.168.xxx.xxx) with Microsoft SMTP Server id 14.3.210.2; Wed, 1 Oct 2014
13:17:22 +0100
Received: from ns5.lucidity.ie (ns5.lucidity.ie [69.36.8.164]) by
xxx.xxx.co.uk (Postfix) with ESMTP id 0C678696B for xxxx@xxxx.co.uk;
Wed, 1 Oct 2014 13:17:10 +0100 (BST)
Received: from fieldandstream.ie ([::ffff:109.229.186.118]) (AUTH: LOGIN
mick@fieldandstream.ie) by ns5.lucidity.ie with esmtp; Wed, 01 Oct 2014
13:11:58 +0100 id 0017605C.542BEF8E.00006496
Received: from rly04.hottestmile.com ([Wed, 01 Oct 2014 16:11:00 +0400]) by
smtp.doneohx.com with ESMTP; Wed, 01 Oct 2014 16:11:00 +0400
Received: from [42.30.29.127] by mail.webhostings4u.com with SMTP; Wed, 01 Oct
2014 16:06:05 +0400
Received: from relay.2yahoo.com ([200.137.192.220]) by mtu67.syds.piswix.net
with SMTP; Wed, 01 Oct 2014 15:50:57 +0400
Received: from relay37.vosimerkam.net ([Wed, 01 Oct 2014 15:43:37 +0400]) by
mailout.endmonthnow.com with ASMTP; Wed, 01 Oct 2014 15:43:37 +0400
Received: from unknown (HELO public.micromail.com.au) (Wed, 01 Oct 2014
15:41:09 +0400) by smtp18.yenddx.com with ESMTP; Wed, 01 Oct 2014 15:41:09
+0400
Message-ID: 7D9E9F4C.AEEB6E0F@fieldandstream.ie
Date: Wed, 1 Oct 2014 15:41:09 +0400
Reply-To: "Barclays@email.barclays.co.uk" mick@fieldandstream.ieFrom: "Barclays@email.barclays.co.uk" mick@fieldandstream.ieMIME-Version: 1.0
To: steve@sueandsteves.co.ukCC: steve@suej.co.uk, steve@suffolk.gov.uk, steve@suffolk.police.uk,
steve@suffolkcartlodges.co.uk, steve@suffolkfada.co.uk,
xxxx@xxxx.co.uk, steve@sugarhouse.co.uk, steve@sumarts.co.uk,
steve@sumlock.co.uk, steve@summe.co.uk, steve@summerbreak.co.uk,
steve@summerleaze.co.uk, steve@summerlin.co.uk, steve@summitbikes.co.ukSubject: =?ISO-8859-1?B?VHJhbnNhY3Rpb24gbm90IGNvbXBsZXRl?=
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
X-sufu-MailScanner-Information: Please contact the ISP for more information
X-sufu-MailScanner-ID: 0C678696B.A7F57
X-sufu-MailScanner: Found to be clean
X-sufu-MailScanner-From: mick@fieldandstream.ie
X-Spam-Status: No
Return-Path: mick@fieldandstream.ie
X-MS-Exchange-Organization-AuthSource: xxx.xxx.corp
X-MS-Exchange-Organization-AuthAs: Anonymous/steve@summitbikes.co.uk /steve@summerlin.co.uk /steve@summerleaze.co.uk /steve@summerbreak.co.uk /steve@summe.co.uk /steve@sumlock.co.uk /steve@sumarts.co.uk /steve@sugarhouse.co.uk /xxxx@xxxx.co.uk /steve@suffolkfada.co.uk /steve@suffolkcartlodges.co.uk /steve@suffolk.police.uk /steve@suffolk.gov.uk /steve@suej.co.uk /steve@sueandsteves.co.uk /mick@fieldandstream.ie /mick@fieldandstream.ie /xxxx@xxxx.co.uk

Bismarck

@FlashPan:

Anyhow below you will see an email header that came into to me to day. Go through Postfix and Mailsanner with no flags.

I think I read it correctly but postfix cannot block email if it passes through or relays through multiple email servers.

X-sufu-MailScanner-Information: Please contact the ISP for more information
X-sufu-MailScanner-ID: 0C678696B.A7F57
X-sufu-MailScanner: Found to be clean
X-sufu-MailScanner-From: mick@fieldandstream.ie
X-Spam-Status: No
Return-Path: mick@fieldandstream.ie
X-MS-Exchange-Organization-AuthSource: xxx.xxx.corp
X-MS-Exchange-Organization-AuthAs: Anonymous

Looks okay for me, this mail passed postfix and mailscanner.

biggsy

@FlashPan:

I think I read it correctly but postfix cannot block email if it passes through or relays through multiple email servers.

I don't think you read that correctly. Do you have a reference?

A lot of email will pass through multiple email servers en route - say, for example, from my mail server to my ISP's mail server to my friend's ISP's mail server and then to his mail server. We both run postfix forwarder on pfSense.

FlashPan

Sadly no I cannot find the webpage again.

My suspicions arose just because of so many relays and the content was definitley spam (trying to make you think it was from Barclays bank- with a non Barclays bank weblink to click on) plus the sender emails address was poorly made to look like it was from the bank as well.

pyrodex

@biggsy:

@pyrodex:

Any chance of getting this to work in 2.2?

Are you talking about Postfix forwarder on 2.2? I have had some problems with that.

Installing postfix on 2.2 (with a config restored from 2.1.5) I'm getting the following:

postfix/postfix-script[56365]: fatal: no Postfix daemon directory /usr/local/libexec/postfix!

and


php-fpm[7873]: /pkg_mgr_install.php: The command '/usr/local/sbin/postfix reload' returned exit code '1', the output was 'cd: /usr/local/libexec/postfix: No such file or directory'
php-fpm[7873]: /pkg_mgr_install.php: The command '/usr/local/sbin/postfix reload' returned exit code '1', the output was 'cd: /usr/local/libexec/postfix: No such file or directory'

Then the following repeats about 5 or 6 times:

php-fpm[8074]: /pkg_edit.php: The command '/usr/local/sbin/postfix reload' returned exit code '1', the output was 'cd: /usr/local/libexec/postfix: No such file or directory'
php-fpm[8074]: /pkg_edit.php: The command '/usr/local/sbin/postfix reload' returned exit code '1', the output was 'cd: /usr/local/libexec/postfix: No such file or directory'

All this could be due to the restored config but I don't know.

Yup this is the same problem I had and I had the same issue on a fresh install too trying everything to get it to work.

Bismarck

FlashPan you definitely need to fine tune your rbl list:

Received: from fieldandstream.ie ([::ffff:109.229.186.118])

Summary information for 109.229.186.118/32
Note: Times shown are for the latest entry only!
Found 2 network entries and 0 host/domain entries.

Problem Entries, (listings will cause email problems.)
1 "Hacked" entries [04:29:20 13 Sep 2011 GMT+00].
6 "Spam" entries [17:17:17 30 Aug 2014 GMT+00].

http://www.anti-abuse.org/multi-rbl-check-results/?host=109.229.186.118

And how often do you update your spamassassin rule subscriptions?

FlashPan

Sigh ??? this is what I am not understanding ;)

My options under Antispam > RBL Server List all seem correct.

zen.spamhaus.org*2, bl.spamcop.net, dnsbl.sorbs.net

As for spamassassin, you just gave me an answer in antoehr threas but think I may have borked the package as now it will not star for some reason.

Getting very close to pulling hair out time :)

Thanks Bismark you are going above and beyond here.

Bismarck

Try this:

recent.spam.dnsbl.sorbs.net2, zen.spamhaus.org, bl.spamcop.net, dnsbl.sorbs.net, b.barracudacentral.org, dnsbl-1.uceprotect.net, ix.dnsbl.manitu.net, bl.spameatingmonkey.net, list.dnswl.org-5

And set RBL threshold 2.

This should keep the most nasty stuff away, you can add how many you like/fit your needs…

Watch it with

tail -f /var/log/maillog

BTW don't use google DNS as your system DNS, use those from your ISP.

http://blog.clairelogic.net/?p=67

cheers!

FlashPan

Thanks for that,

Yep I had my 3 rbls and threshold set to 2.

Have updated to the rbls you've given but still no joy now. Before MailScanner died on me emails were blocked from http://www.crynwr.com/spam. Now MailScanner has gone these emails are getting through.

Sadly from Saturday I am away for the next 2 weeks. I think I need to step back from this and completely remove postfix and mailscanner and re-install them from scratch (if only for my own sanity :P)

I'm very sorry about this especially to you Bismarck as you have tried very hard to help me and I really do appreciate all your input and help.

Before I depart though I know that simply uninstalling both packages will not remove the config settings I've made. I've been scouting around but from where would I find these configs to delete directly? As I said want to start with a clean sheet.

So if I get the 2 packages removed expect me back here in about 2.5 weeks crying again :)

Cheers all

FlashPan

Well this will be my last reply before I disappear for the next couple of weeks.

My postfix is now working and the rbls are blocking as they should. Removed postfix, removed anything left behind after uninstall and re-installed. (My original config was still intact though - would still be nice to find out where that is stored?)

I also discovered a misprint for an acl section

Access Lists > MIME:

The example says to use /^name=[^>](com …........etc to block certain file extensions. For me this does not work. I've used /name=[^>](com …........etc remove the ^ and loose the text after /REJECT

I've tested this by emailing myself a test file with a safe extension like .bit Added .bit into the string and that email does not get to me and a bounce back is received to the sender.

"Server refused mail at END OF DATA - 550 5.7.1 message content rejected"

If I didn't make the changes above the email and attachment would still come through.

Hope this helps someone :)

My Mailscanner is still shot, something to do with perl and EN language settings I think??? But that's for the other thread and when I get back.

Cheers

ApolloDS

If you need TLS Config you have to put the following into the "custom main.cf options" Field:

# 20141006 Add TLS
#
# SMTPD
#
smtpd_tls_cert_file = /cf/conf/cert.crt
smtpd_tls_key_file = /cf/conf/cert.key
smtpd_tls_CAfile = /etc/ssl/cert.pem
smtpd_tls_security_level = may
# SMTP Client
smtp_tls_security_level = may
smtp_tls_CAfile = /etc/ssl/cert.pem
# SSL-Certificate - Generate logfile entries
#
smtpd_tls_received_header = yes
smtp_tls_loglevel = 1
smtpd_tls_loglevel = 1

You need to upload the Cert Files to /cf/conf.
I hope this path is upgrade-save, I couldn't test it yet.

Maybe someday we can use the Cert Manager Certs of pfSense in Postfix Forwarder Package? ;)

Best regards,
Peter