Cyrus Protocol Logging
As a debugging aid, Cyrus IMAP can also log protocol conversations on a per-user basis. Note that you cannot debug the authentication process using this, because the protocol logging is only associated with a username and until a user has been successfully authenticated, the username is unknown.
To enable protocol logging, simply create a directory in /var/lib/imap/log with the user's name you wish to log. Ensure, of course, that this directory is writable by the user Cyrus runs as. Cyrus will create files in this directory with the name of the process ID under which it runs (which changes per connection due to the forking server model it uses).
# cd /var/lib/imap/log/
# mkdir wcooley
# chown cyrus wcooley/