Minecraft – Constant LAN port

Occasionally, a friend wants to join me, playing on my Minecraft world, which I run locally on my computer.

We don't want to use VPN or other stuff, so we currently do it using this procedure:

1. I start Minecraft, load my world, then click "open to LAN". I note the random generated port.
2. I open my NAT router configuration and forward that port to my computer
3. I open that port in the Windows Firewall.
4. I look at myip.is to find out my current public IP, which changes every 24h.
5. I give my buddy my public IP address, and the port, so he can connect to "[ip-address]:[port]"
6. After the game session, I will remove the port from the NAT Port forwarding table and in the Windows Firewall (because it will be invalid in the next session)t

I do know that step 4 can be dropped if I use a Dynamic-DNS service. I think I will set one up.

But I find it very annoying to always re-configure my Windows Firewall and the NAT Port Forwarding Table, just because Minecraft always listens to a random port.

What can I do to make the procedure more easy? Can't I simply tell Minecraft to always use the same port when playing "local" in LAN (actually WAN, because I use port-forwarding).