mdflagwriter using port 21? I have a 17" mid 2010 MBP with 8GB ram.

After reading up on some of the latest vulnerabilities, I did a port scan and found port 21 OPEN vs stealth for all other ports. I cannot figure out what is using port 21, but Activity Monitor shows ports 21 and 24 being used by mdflagwriter (see attached screen shot)

Why would a Spotlight indexing system be using these ports, and how do I close port 21?  The other two show as stealth, but 21 seems to be open.  Is it safe to just kill these pids?

Stealth mode is enabled in System Preferences->Security &amp; Privacy.

Thanks for any answers.
The word "Ports" here does not mean what you think it means. It is not the number of a single TCP or UDP port the process has open. It is not even the count of such ports.

'The "ports" column shows how many "Mach ports", or "kernel queues" the process has open, which basically describes how communicative the process can be with others (eg: reserving memory usage from the system). This information will only be useful to system administrators and programmers.'