This command is used to train the anti-spam filter. This command is run automatically every night to train the SpamAssasin filter from messages users mark as “junk” “not junk” from their mailbox. See Zimbra MTA, Anti-Spam Training Filters.
You need at least 200 spam & 200 not-spam to enable the bayes filter. You can use this command to manually send one account’s mail through the spam filter.
zmtrainsa <server> <user> <pass> <spam|ham> [folder ]
zmtrainsa fetches the mail from <user> with password <pass> from <server> and trains the filter as either spam or ham <spam|ham>. The folder is optional. If a folder is not defined, the contents of the Inbox is fetched.
After 4.5.5 password is no longer needed:
Usage is : /opt/zimbra/bin/zmtrainsa <user> <spam|ham> [folder]
No Password required. Server name required if in a multi-server install. For 'user' put email address.