Postfix configuration & control

First the bad news/confession: Somehow PostFix has been running on my X Server with an open relay, and some spammers found it. Now the observations: 1. Server Manager says Mail service is not running. 2. The Postfix 'master' process is running. 'ps' shows just the entry "master", not the fully qualified pathname that other services have displayed in 'ps'. 3. Thankfully, this master process does respond to the PostFix configuration files. 4. However, if I issue 'postfix stop', it'll start itself back up again 5. A friend showed me the lines in master.cf that turns off the various ports. The spammers seemed to be coming in on the Submission port, rather than the SMTP port. Finally some questions: 1. Which process (and its config files) controls the launching of PostFix? I'd rather turn this off at the source. (launchd?) 2. Any ideas why Server Admin says 'mail service is not running' when PostFix is out there being very naughty? 3. I thought Apple PostFix configurations were "open-relay-proof' out of the box. Any idea why this configuration is accepting spam? Thanks in advance, as usual. dave