Getting the syntax right is hard! And it's hiding under /usr/local/cyrus/sbin/
https://www.linuxquestions.org/questions/linux-software-2/cyrus-ipurge-not-working-317640-print/
The 5 advanced rsync tips are also very handy.
This is the one I installed in the 90's on my home machine, and used in conjunction with fetchmail to retrieve messages over POP. Always the rebel, I had to try something besides mail and pine, and elm seemed too similar to both.
Specifically, it tells how to ship Apache and Nginx logs over rsyslog.
IPBan: https://www.digitalruby.com/ipban/ [Windows/Linux only]
SSHguard: http://www.sshguard.net
Sentry? https://github.com/msimerson/sentry/ [Perl, not sure how automated it is]
For Linux, dovecot, and rainloop, but the postfix stuff is useful
It describes using IIS as the proxy, in addition to Nginx and others.
