Q about port useage

[MonsterDK]

On a dedi I have servers running on ports 27017, 27018, 27019

I was unable to use 27020, 27021, 27022 is this because each of the servers above have in turn reserved those ports for the likes of SourceTV which from what I have read starts at default on port 27020 ?

But if none of the servers are using SourceTV then should they still be reserved?

I don't know even know if i'm on the right tracks here. Would someone please put me out of my misery (not literally).

[Drocona]

None of those ports are "reserved" they are just in use when you run sourceTV.

just like port 27015, if you are not running a server another application can use it. but not 2 applications at the same time.