This link wont fix your problem but is invaluable when trying to analyse it.
the tabs on the left,
the links especially the Wikipedia link,
you can click on the ports on the right then click the check button,
you can input the port number manually and check its status by clicking the "check" button.
As far as I am aware port forwarding problems relate to the router and firewall and not the OS.
It may help if you could post back your router make & model, the firewall you are using and what you are trying to do then maybe someone will come forward.
As I said, I already disabled firewall and I looked up "how to portforward" multiple times - even tho I know how to do it, as i mentioned in one of previous posts - I already had server up for minecraft, two years ago.
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