I've just set up IMAP/POP proxy with ZCS 4.0.2NE in preparation for a multi-server configuration. I've discovered that by default the perdition config sets debug=on and connection_logging=on. This is a Very Bad Thing to do by default. This logs all traffic to/from perdition, including passwords. I've disabled it in my config, but the Zimbra team should strongly consider changing this for upcoming releases.