Default LaunchDaemons and open ports?

Question

I recently have written a port scanner for a project at my university and after running it, I discovered that a large portion of my Macbooks' well known ports was open.
These were 21 (ftp), 22 (ssh), 23 (telnet), 53 (domain), 79 (finger)!!, 88 (kerberos), 512 (exec)!!, 513 (login), and a bunch of others (see picture below for open ports - afterwards entered @ grc.com).
I checked, if they are reachable from the internet (see picture below). They were not, but that does not say a lot(?), because if someone wanted to make a bot out of my Mac or collect data from it, this person could contact a C&C server from my machine and start communicating without opening any port of the NAT router, as the router allows bidirectional communication if started by the client(?).
I checked, if these ports are reachable from within a local network, by requesting the services behind them from another computer running Linux. And they are! Everyone within the Non-VPN networks of my university was and is able to fetch personal information from me over fingerd! To prevent further leakage, I will block any incoming connections from now on.
> finger user@{Macbook's IP}
same output as when running locally
> finger user@localhost
[localhost]
Trying ::1...
Login: MyUserName         Name: MyNameReplaced
Directory: /Users/MyUserName            Shell: /usr/local/bin/fish
On since Sun Oct 26 13:02 (CET) on console, idle 7:52 (messages off)
On since Sun Oct 26 17:15 (CET) on ttys000
On since Sun Oct 26 20:25 (CET) on ttys001, idle 0:05
No Mail.
No Plan.
I am able to login to the Mac via telnet over the LAN, etc.
I checked the configuration of my firewall. It is/was activated. Signed software is allowed to accept incoming connections. Cloaking is not activated and I am not blocking every incoming connection. There are five services in the list below, they are all from Apple. I can not remove them. The minus button is grayed out.
When I ticked 'Block all incoming connections', the services behind the ports were no longer detectable/reachable from the LAN, but the daemons are still running on the Mac!
So my question is, why are these daemons running?! Why on earth is the fingerd running or exec?! This seems not normal. Who has started them (software or person)? I strongly limit access to my computer. I always lock it, when leaving it unattended. I use NoScript in Firefox. Never do I open attachments from mails.
I checked the Mac of a friend with my PortScanner (in his LAN and on his Mac) and his has none of the ports open mine has.
I have not checked my ports/firewall for a long time, so I can't remember if those ports were closed at any time before.
Meanwhile I will read something about launchd, to gather more information.

Answer 1

I'm not an expert on this, but I'm not certain what you are concerned about. All messaging in unix systems is done through ports, and so a variety of ports need to be open for normal system operations. OS X out-of-the-box probably strikes a balance between convenience and paranoia - ports that might be more secure closed left open by default so that novice users aren't driven out of their wits - but I can't imagine that it leaves open anything that constitutes a true vulnerability. Or if it does, you should file a bug report.
I'm told every med student suffers from hypochondria at one point or another, and I know that every comp sci student will sooner or later have a short freak-out over security. So take a deep breath...