Why does port scan show an open port for application I've never had?

Question

I don't currently and never have used Bacula to backup my Macbook, but for some reason when I do a portscan it often shows a Bacula file daemon being open on port 9102.  It also comes up in Netstat as listening, even with my firewall blocking all unnecessary connections, sharing turned off (all), and an Airport ex in front of it also secured.  I also cannot find any related files etc. on my machine after a thorough search.  Despite my best google and support searches, I couldn't find anyone with the same problem.  Is this reason for concern? Either way why would it be there despite it not being ever used on my Mac?  I am not well versed in networking, only know enough to get myself in trouble, so thanks in advance for any help.

Answer 1

Ok, I ran a port scan on 9102 and it show it's not responding, but assigned to (bacula-fd)
So what it appears to be is Bacula ( a legitimate program) uses this port, much like Screen Sharing uses port 5900, not necessarily that it's installed on your machine.
It's not uncommong to have open ports, it's so if you ever install the program or use a service it can gain access through the Firewall. You can change that of course to close up everything except certain ports for certain programs.
Now that the firewall is App based, if you don't have the app listed, how do you deny it access?
Well if the program isn't installed on the machine, it can't respond if the port is open or closed.
Simply enable your Firewall and allow the programs you do have and want to access your machine to connect in the Advanced settings.
There is also NoobProof and WaterRoof if you need a GUI/simplicity to enact more complex features of the command line firewall. Block IP addresses and everything. However read up before you mess around, Apple has everythign set up nicely and there are very few successful attacks on Mac's.
If you don't know what your doing, you can actually do more harm opeing up your machine to poential attack.
If your more paranoid, then install LittleSnitch, it's a outgoing firewall and notification software with pop-up window to allow/deny on a per program or request basis. You'll be quite shocked how much is going out in the background without your knowledge.