In hoping to answer your original question, I'll copy a quick guide I made for port forwarding elsewhere.
So I know there's issues still with connecting to servers that are hosted from a player, and not from a hosting service. This involves some port forwarding to resolve, which not everyone may be familiar with. It's half-way easy once you know what to do, so hopefully, this somewhat step-by-step guide will get you hosting servers like we all once easily did.
Step 1: Find the IP Address of your computer. To do this, open up your Command Prompt. Hold your Windows key and press 'R'. This opens the run command, and in that bar, type 'cmd', and press enter. A small black screen with white text will appear, and this is what we want.
In this box, type 'ipconfig /all'. It will populate quite the list of names, numbers, and all sorts of jargon. Don't worry about this. Depending on how large you've made the CMD box, scroll back up to the top. You are looking for the second set of information titled 'Ethernet adapter Local Area Network'. For myself, halfway down the list (on the left hand side). and what we're looking for is IPv4 Address. If you follow its dotted line to the right, you'll see the IP Address if your computer; this is important, so either write it down, or keep the CMD window open.
Step 2: Forward ports on your router. Typically, most routers IP Address is 192.168.0.1, or 192.168.0.2, though this isn't always the case. If either of those two don't work, a simple Google search of your router brand will reveal what they're using. Now in your browser bar (where a website would be), type in said router IP address. After a moment or two, you should be greeted by a log-in screen. Now if you haven't changed the routers log-in name and password, you can find it by physically going to your router, flipping it over, and finding the sticker on its bottom. It'll have the default user name and password, so plug those in, and you're money.
Note: sometimes, though not often, the password written is not the password used. In such cases, either contact your ISP and find out what it is, or a simple Google search usually reveals other potential passwords.
Step 2, A: Every interface is different, but what we're looking for is typically labeled 'Advanced Settings', or something along those lines. When you click on that, it usually populates quite a lot of various sub-settings. My own router has Port Forwarding set up under Security, though that may not always be the same for everyone else. After finding and clicking on Port Forwarding, it will populate a screen with various fill-ins.
Step 2, B: Again, every router is set up a little differently, but what we're looking at fiddling with should be universal. There should be an IP Address part, and in there, is where we enter the IP Address we found up in Step 1.
Next is usually 'Starting Port', and 'Ending Port'. Your Starting Port will be 2302, and the Ending Port will be 2303.
Next should be Protocol. Mine is defaulted TCP, as many are, but for Arma3, it needs to be set to UDP. If there's an option for TCP and UDP, that should be fine as well (though UDP has been tested to work fine).
After that, depending on how your interface is set up, either simply save as is, or save it as a set of rules (named Arma if you want).
Step 3: Play Arma 3. This step is pretty self-explanatory. If everything was entered correctly, people should be able to find your sever with relative ease.
Hope this helps!