In OS X 10.6.5, the following dialogue popped up:

What is this application? What does it do?


EDIT (to increase googlability): OS X firewall: Do you want the application "master" to accept incoming network connections?

  • 3
    You should copy the message text and quote it in your question, so others have the chance to google for the dialog text and find this topic when they have that same issue. – Daniel Beck Jan 16 '11 at 20:07
  • @Daniel, it's already in the question title so it's on the page and thus should be findable. – Joey Jan 16 '11 at 20:08
  • @Joey Compare the question title and the dialog box screenshot. Note that none of the terms is useful on its own. – Daniel Beck Jan 16 '11 at 20:15
  • @Daniel Beck, good idea. – trolle3000 Jan 17 '11 at 20:59
  • Are you using CronniX? The same confirmation dialog pops out on my screen, but only at the times I have a cronjob set via CronniX. – user61429 Jan 18 '11 at 7:35

"master" is part of the Postfix mail server system that comes installed by default on every Mac. It is usually disabled, I can't say why it might be activated.

  • Interesting. Do you know where I can find a description of this? – trolle3000 Jan 20 '11 at 0:07
  • 1
    For postfix, postfix.org. For master try man master. – bahamat Jan 20 '11 at 2:16
  • This was triggered during a wordpress install for me–I presume whatever you were doing prompted the system to send an email. – adamdport Feb 28 '15 at 16:49

I use OSX 10.8 with the server app, and this message appeared to me after: - I activated mail notifications about network modification, etc. of my server - I installed 10.8.1

So, I think it's the reason why the postfix mail server is started & why the message has appeared (it's my first reboot since my 10.8 upgrade 3 weeks ago)

  • This is likely. To me it showed up after configuring a local Wordpress installation (using the local apache server), which requries an administrator email to be provided. The installer sends a welcome email to that address. – Víctor López García Aug 25 '14 at 17:37

That looks fishy to me. Open up Activity Monitor, look for a process named "master," and then find the location of the executable by running $ ps -ax|grep the_PID_from_activity_monitor in Terminal.

That might give some insight.

  • Nothing called 'master' appears in Activity Monitor. It appears in the Firewall Pref Pane since I blocked it; the icon is the generic "UNIX Executable" one. – trolle3000 Jan 17 '11 at 21:01
  • If you denied it from connecting to the internet it may not have actually opened, so that could explain not seeing it in Activity Monitor. Change "My Processes" to "All Processes" in activity monitor to be sure though. You could also try searching for it with EasyFind devon-technologies.com/download/index.html which will search all of the drive, not just what Spotlight can search. It will also let you search inside packages, as this application may be inside another application. On my Mac for example I have a file called master inside Choosy prefpane & one in the postfix directory. – ridogi Jan 17 '11 at 22:51
  • You could probably also do this with the find command in Terminal, looking for an executable file with the name "master." I'm not sure exactly what that command would look like at the moment, but I'm pretty sure it's possible. – NReilingh Jan 18 '11 at 0:02

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