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Centos 7 | Postfix + Postgrey and other SPAM evasive actions
#1
Centos 7 | Postfix + Postgrey and other SPAM evasive actions
Say bye bye to huge amount of SPAM messages with this simple to install daemon.


Install Postgrey:
Code:
yum install postgrey

edit this file
Code:
vi /etc/sysconfig/postgrey

and change this line from
Code:
POSTGREY_OPTS="--delay=60"
to
Code:
POSTGREY_OPTS="--delay=300"

Start the service and make sure that daemon is automatically started after reboot:
Code:
systemctl start postgrey
systemctl enable postgrey

OK. Now we need to tell Postfix to start using Postgrey and also set some other SPAM evasive actions

Edit the file:
Code:
vi /etc/postfix/main.cf
… find this “block”
Code:
# rules restrictions
smtpd_client_restrictions =
smtpd_helo_restrictions =
smtpd_sender_restrictions =
smtpd_recipient_restrictions = permit_sasl_authenticated,
       permit_mynetworks,
       reject_unauth_destination,
       reject_non_fqdn_sender,
       reject_non_fqdn_recipient,
       reject_unknown_recipient_domain
# uncomment for realtime black list checks. (Warn: will also reject false positive)
#       ,reject_rbl_client zen.spamhaus.org
#       ,reject_rbl_client bl.spamcop.net
#       ,reject_rbl_client dnsbl.sorbs.net
… and replace it with this one:
Code:
# rules restrictions
smtpd_client_restrictions =
       permit_mynetworks,
       permit_sasl_authenticated
smtpd_sender_restrictions =
       permit_sasl_authenticated,
       permit_mynetworks,
       reject_non_fqdn_sender,
       reject_unknown_sender_domain,
       permit
smtpd_recipient_restrictions =
       permit_mynetworks,
       permit_sasl_authenticated,
       check_policy_service unix:/var/spool/postfix/postgrey/socket,
       reject_invalid_hostname,
       reject_unauth_destination,
       reject_non_fqdn_sender,
       reject_non_fqdn_recipient,
       reject_unknown_recipient_domain,
       reject_unauth_pipelining,
       reject_unknown_sender_domain,
       reject_unknown_recipient_domain,
# uncomment for realtime black list checks

       reject_rbl_client sbl-xbl.spamhaus.org,
#       reject_rbl_client multi.uribl.com, ### Too many requests - payable service
       reject_rbl_client dsn.rfc-ignorant.org,
       reject_rbl_client dul.dnsbl.sorbs.net,
       reject_rbl_client bl.spamcop.net,
#       reject_rbl_client dnsbl.sorbs.net, # Emails from yahoo are blocked with this one
       reject_rbl_client cbl.abuseat.org,
       reject_rbl_client ix.dnsbl.manitu.net,
       reject_rbl_client combined.rbl.msrbl.net,
       reject_rbl_client rabl.nuclearelephant.com,
       permit

below that block find this line:
Code:
smtpd_data_restrictions = reject_unauth_pipelining
… and replace it with:
Code:
smtpd_data_restrictions =
       reject_unauth_pipelining,
       permit_mynetworks,
       permit_sasl_authenticated

One last thing…
find the line:
Code:
message_size_limit = 20480000
… and paste the following before that line:
Code:
# Try to resend mail after 15 min
transport_retry_time = 15m

# More anti-spam checks

smtpd_delay_reject = yes
smtpd_helo_restrictions =
   permit_mynetworks,
   permit_sasl_authenticated,
   reject_non_fqdn_hostname,
   reject_invalid_hostname,
   reject_unknown_helo_hostname,
   permit

Save and close the file and restart the Postfix
Code:
systemctl restart postfix

Just to make sure that Postgray is working, check the maillog:
Code:
tail -f /var/log/maillog

… and send a mail from external (non hosted) domain. Note: google and bunch of others are Whitelisted by default.

You should see a line like this:
Code:
Feb 00 00:00:00 host postgrey[122947]: action=greylist, reason=new, client_name=mail.domain.com

Thats it! You’ve dramatically reduced the amount of SPAM messages =)
Reply
Thanks given by: Qtech , wormsunited
#2
RE: Centos 7 | Postfix + Postgrey and other SPAM evasive actions
Hello have you installed RRDtool with this as well. If so would you care to show us a guide.
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#3
RE: Centos 7 | Postfix + Postgrey and other SPAM evasive actions
Thank you, thank you, thank you.
Smile
Reply
Thanks given by:
#4
RE: Centos 7 | Postfix + Postgrey and other SPAM evasive actions
I made all steps, going to check if they work, even so huge contribution to the community, thanks a million times!
'' Life is full of important choices ''
Help Sentora Donate now => http://sentora.org/donate Blush
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Thanks given by:
#5
RE: Centos 7 | Postfix + Postgrey and other SPAM evasive actions
Hi there, by far this made a reduction of 80% on the spam indeed. Great post highly recommended.
'' Life is full of important choices ''
Help Sentora Donate now => http://sentora.org/donate Blush
Reply
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