block mails from a particular country in postfix

Is there any possibility to block mails from country wise in Postfix. for Example I need to block all mails coming from China. Please let me know the process.

Thanks,
Vijay.G

Vijay Kumar GajulaAsked: 2017-03-27

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LVL 11

Tim EdwardsIT Team Lead - Unified Communications & CollaborationCommented: 2017-03-27

Please take a look here, they were able to get this completed with Postfix:

http://freesoftware.zona-m.net/how-to-reject-spam-from-certain-countries-if-you-must-really-really-do-it/

LVL 13

Kent WSr. Network / Systems AdminCommented: 2017-03-27

The most straightforward way is blocking the /8 IP block of the associated country, via iptables.
The list of IPv4 is here - http://www.iana.org/assignments/ipv4-address-space/ipv4-address-space.xhtml
Ipv6 is here - https://www.iana.org/assignments/bgp-extended-communities/bgp-extended-communities.xhtml#non-trans-ipv6

Regardless of your postfix config, if you block via iptables rules, they won't be able to get mail or any other packets to your server...like bruteforce, etc.

LVL 83

arnoldCommented: 2017-03-27

http://www.postfix.org/addon.html has references to enhance functionality.
Blocking by firewall could lead to dos since there is a resource for blocking and attempts will be retried ..
Using rbl that will mimic an SMTP session and issue a permanent error when the recipient is identified in the SMTP session.

Rbl, you would use an internally created ..........

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LVL 14

Natty GregIn Theory (IT)Commented: 2017-03-29

Use PFblocker

Vijay Kumar GajulaAuthor Commented: 2017-03-30

is PFblocker is open source? can we install it in my mail server which is UBUNTU back-end. If So Please let me know the procedure.
Thanks

LVL 14

Natty GregIn Theory (IT)Commented: 2017-03-30

Yes PFblocker is open source, however it only installs on PFsense from what I know and found. So maybe use PFsense as your firewall then you'll have all this functionality