I have been looking into exactly the same, don't know how I am going to implement it still. What I know for now.
This is how you can get info on a netblock owner. [@]$ dig +short -t txt 80.53.103.176.origin.asn.cymru.com '48031 | 176.103.48.0/20 | UA | ripencc | 2011-12-09' You can then either decide to mark everything as spam with spamassassin or block reject it via a milter or so. Combined with this you can then whitelist only this networks official outgoing smtp servers. -----Original Message----- From: Alex [mailto:mysqlstud...@gmail.com] Sent: Sunday, October 25, 2020 6:50 PM To: SA Mailing list Subject: Blocking by country/ASN/IP/domain Hi, I have a spamassassin-3.4.4 install with amavisd-2.12 and postfix on fedora32 and would like to be able to block email from an entire country on a per-user or per-domain basis. What is the best way to do this? I'm currently using the RelayCountry plugin and Amavis::Custom to add an X-Relay-Countries header to each email, and have a series of rules of the form: header RELAYCOUNTRY_JP X-Relay-Countries =~ /JP/ describe RELAYCOUNTRY_JP Relayed through Japan score RELAYCOUNTRY_JP 0.1 I've also been considering blocking by ASN or IP, but I believe it would be the same problem just presented in a different way. How do I tie this into amavisd so that I can allow individual users to control their own email? Perhaps this is done in a policy_bank? Perhaps I would analyze the X-Relay-Countries header directly instead of processing the resulting RELAYCOUNTRY_JP rule, for example?
