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Postfix Email Servers can filter or Reject Spam

Open Source spam solution

This is the simplest solution for rejecting 90% of spam with no false positives For your Postfix Email Server.

smtpd_recipient_restrictions =
permit_sasl_authenticated,
reject_non_fqdn_recipient,
reject_unknown_recipient_domain,
permit_mynetworks,
reject_unauth_destination,
reject_rbl_client zen.spamhaus.org,
reject_rbl_client bl.spamcop.net

This makes your Postfix email server reject mail from servers that are known to send spam. Spamhaus and spamcop aren’t self righteous.

Make your life easy and perform a simple installation method, Install Postfix Email Server with Webmail, Https Cert, Easy User Admin

Also see

https://rspamd.com/doc/quickstart.html

https://www.vultr.com/docs/simple-mailserver-postfix-dovecot-sieve-centos-7

https://www.vultr.com/docs/simple-mailserver-postfix-dovecot-sieve-debian

More ideas for getting rid of Spam on your Postfix Email Server

I am using

Amazon Linux 2
dovecot 2.2.33.2
spamassassin 3.4.1
amavisd

The goal is to run an e-mail server, which I achieved already. I can access the e-mails at the server using Thunderbird and the imap protocol.

For the postfix configuration I followed this tutorial: https://help.ubuntu.com/community/PostfixBasicSetupHowto but using Maildir instead.

Dovecot got configured following:

https://www.linuxbabe.com/mail-server/secure-email-server-ubuntu-16-04-postfix-dovecothttps://help.ubuntu.com/community/Dovecot

In addition I installed fail2ban, which got tested successfully.

The next step is e-mail filtering. Following https://help.ubuntu.com/lts/serverguide/mail-filtering.html.en worked out nicely. Spamassassin is blocking all spam. But acutally I do not want to block it, I just want that spamassassin marks it as spam and that the spam gets redirected into my spam-folder. This is just in case something gets filtered out that was not a spam.

For that I set /etc/amavis/conf.d/21-ubuntu_defaults:

$final_spam_destiny = D_PASS;

and the subject gets added ****SPAM****

The next step is that dovecot automatically moves this mail to my junk folder. And there I get stuck. I followed this tutorial: https://workaround.org/ispmail/stretch/filtering-out-spam-with-rspamd

and there the part “Sending spam to the Junk folder”. But it doesn’t work. I have seen that sieve is not working for imap. But I cannot find any tutorial or manual on imap_sieve, that would solve my problem. Does anyone of you has an idea? I also do not find any log entry where I could see that sieve is working (or not)?

down vote

I got a bit further in my problem:

By setting conf.d/10-logging.conf

mail_debug = yes

and conf.d/90-sieve.conf

sieve_plugins = sieve_imapsieve sieve_global_dir = /etc/dovecot/sieve/`

as well as in:

conf.d/90-plugin.conf `

plugin { sieve_plugins = sieve_imapsieve sieve_extprograms imapsieve_mailbox1_name = INBOX imapsieve_mailbox1_after = file:/etc/dovecot/sieve/default.sieve sieve_global_extensions = +vnd.dovecot.pipe +vnd.dovecot.environment }

and sieve/default.sieve: `

require [“fileinto”, “mailbox”, “imap4flags”]; if header :contains “subject” [“*SPAM*”] { setflag “\\Seen”; #setflag “\\Deleted”; fileinto :create “Junk”; stop; }

as well as compiling by sievec sieve/default.sieve I made it that junk mail gets copied into the junk folder. But unfortunately the mail stays as well in the Inbox. It seems it is just copied?