rspamd is great, but it works the system. When a spammer sends a lot of email, rspamd has to scan every one of them. Better to block the spammer outright.

Hackers are constantly trying to break in. As a rule, most (all?) of these attempts are logged in /var/log/auth.log, so there's a good way to detect them and block them with a shell script.

There's a simpler way (however, it leaves the rsyncd daemon running on the host):

1. in rsyncd.conf:
   1. hosts deny = 0.0.0.0/0
   2. hosts allow = localhost
2. from the client:
   1. ssh -L <some_local_port>:localhost:873 remote_host
   2. rsync <options> rsync://localhost:<some_local_port>

Short answer: diskutil resetUserPermissions / <id> (or `id -u`)

How to fix permissions issue on Catalina OSX

Good article convert from using the rsyncd server daemon to a pop-up daemon behind ssh. Essentially:

• A special rsyncd.conf file on the host to be backed up that provides a read-only view of the filesystem, with optional includes/excludes (see the rsync man page for details). Example:

There doesn't seem to be an internal dovecot tool for eliminating duplicate emails -- and over time, duplicates seem to accumulate endlessly.

My strategy: import the mailbox to DevonThink Pro, which automatically ignores duplicate imports. Then export the messages to an mbox. Use BBEdit to replace the " " with a newline (to properly delimit messages), import the mbox into Mail, and then rebuild the final mailbox so that Mail correctly indexes attachments.

• Install.
• to add whitelist and blacklists, read this, and add map (*.inc) files to local.d, chmod a+w, and edit rspamd.conf.local appropriately.