Postfix Study

Postfix: 

https://www.pc-freak.net/blog/list-mail-queue-qmail-sendmail-postfix-exim-smtp-server/

https://words.bombast.net/rspamd-with-postfix-dovecot-debian-stretch/

https://help.nextcloud.com/t/tutorial-your-own-mail-server-dovecot-postfix-rspamd-with-tight-nextcloud-on-apache-integration-for-debian/33116/18

https://pieterhollander.nl/post/mailserver/

https://gist.github.com/ibqn/22b9c1726dae656f295a9060fb758d15

Postfix with RSPAMD

https://unix.stackexchange.com/questions/684694/rspamd-ratelimit-doesnt-work

https://123qwe.com/tutorial-debian-9/

https://www.howtoforge.com/replacing-amavisd-with-rspamd-in-ispconfig/#make-rspamd-dashboard-accessible-from-outside

https://news.ycombinator.com/item?id=16238845

https://www.c0ffee.net/blog/mail-server-guide/

https://docs.nethserver.org/projects/nethserver-devel/en/latest/nethserver-mail.html?highlight=smarthost

https://www.ws.afnog.org/afnog2019/sse/rspamd/rspamd_intro.pdf

https://forum.aapanel.com/d/12801-mail-server-rspamd-error/32

https://p5r.uk/blog/2021/dkim-setup-with-postfix-and-rspamd.html

MTA-STS

https://aykevl.nl/apps/mta-sts/

IMAP Sync

https://pieterhollander.nl/post/migrate-mail-imapsync/

FBL

https://fbl.validity.com/manage

policyd server

http://policyd.sourceforge.net/readme.html

https://dhenandi.com/how-to-integrate-cbpolicyd-in-mailborder/

Postfix

https://docs.iredmail.org/index.html

AmavisD

https://docs.iredmail.org/disable.spam.virus.scanning.for.outgoing.mails.html

Anti-virus:

Kaspersky Security 8.0 for Linux Mail Server

Proxmox

https://tweenpath.net/category/virtualization/proxmox/

Postfix Rate Control: 

https://www.postfix.org/TUNING_README.html#server_tips

https://talk.plesk.com/threads/postfix-rate-limiting.322831/

https://vinters.com/blog/rate-limit-outbound-mail-in-postfix/

https://making.pusher.com/per-ip-rate-limiting-with-iptables/

http://en.redinskala.com/category/mail-security/

https://serverfault.com/questions/1100214/can-postfix-log-source-ports-for-inbound-smtp-connections