

Port forwarding and static IP are kind of different things. I don't know Arma3 and what hosting involves, but unless its just for a specific temporary instance for you to use at that time, you would definitely be in violation of your ToS for your ISP if you were creating a server for others to use without you being involved concurrently. Sometimes they call it a DMZ device where the firewall will forward all undefined traffic to a specific internal IP. The gateway/firewall device you have should have settings for this. traffic comes in and out of ports, but generally it goes to your modem/gateway which if something comes in without an outbound request, the modem doesn't automatically know what internal device to forward it to. Port forwarding is a totally different subject and I"m not sure what you are really trying to do here. The terms of service for residential connections all specifically state that you cannot host a server which is why none will provide you with a static IPs. Not to be snarky, but "I want to host a server" directly conflicts with "I won't pay for business class service".
