If this is enabled, it won't work.
Usually, whenever you activate the network on a new application, windows asks you to add it to the list, and has preselected one of the options. Just leave it on this option and accept.
If things don't work out, then maybe something went wrong here. Allow both private and public networks. The reason I say this is because I've tried to get something to work for hours, and this right here was the problem.
Look at the output of ipconfig, and look if you don't have weird network adapters.
For example, VMware network adapters / Virtualbox network adapters. If you have those, make sure you disable these before hosting a game, as these will make your local IP different. And I'm not sure if changing the setting within the router fixes this, as the router might still think you're on the other IP, so stuff is routed within an extra layer I guess, which messes up things.
Within ethernet properties, disable any bridging stuff, IPV6 stuff, Npcap
You can either google it, or (with the game running and hosting a server) use Resource Monitor ( included within Windows Vista / Later ), and go to Network tab, Listening ports, and the process / port(s) should show up.
Figure out how to get to your router page, and then forward the ports there.
It will be on something that starts with 192.168. For me it's on:
Make sure that the local IP (192.168.x.x) of your computer is correct within the port forwarding settings.
You can find it through cmd ipconfig, scroll up and on the line that says: IPv4 Address. . . . . . . . . . . : 192.168.x.x
Also make sure that any enabled check is checked on
For some reason, for me, I had to disable IPV6 in order to get UDP working. TCP worked fine with IPV6, but UPD apparently doesn't for whatever reason.
But then later, I reenabled IPV6, and things still worked, so IDK.
Start hosting your game.
First we're going to see whether something is hosting. open the powershell, and type netstat -an and look for any like with :PORT_NUMBER, for example, in my case, hosting a quake game, there was 1 line saying the following: UDP 192.168.2.1:26000 *:*. If this does not stand there, it might be a problem with the firewall, or with the game itself.
If things work correctly, go to. https://www.yougetsignal.com/tools/open-ports/ and check if each port is open (TCP only, UDP is not supported here).
If any 1 of the ports is open, things will most likely work.
If you want to scan UDP, consider using nmap ( https://nmap.org/ ). See below on how to use it. nmap also works for tcp
Consider opening windows defender firewall with advanced security , And then whitelisting the application / ports manually there.
Or try to remove the applications within firewall, and then starting them back up again
Findable on your modem/router page
I've set it so that it allows most things, except for some other things.
It might be the case that a different program is already using a specific port, so you may need to find that program, and stop it, or if the game allows it, use a different port number.
check if the other person isn't on a different WIFI network which is seperated from your main WIFI network.
for TCP cmd/terminal: nmap IP -p PORT
Example output:
PORT STATE SERVICE 26000/tcp filtered quake
Only when state says: open, it works on tcp. If it says filtered, it still might be working, but on UDP.
To check UDP, try nmap -sU -sV -p <port(s)> <target>
Note that this tool might get stuck on "Starting Nmap ..." for a long time.
Also note that the second time you run a scan after the first one is finished, it might give a different result if the first one wasn't very descriptive.
When I have an UT99 server running (newest patch as of 2025), the output of nmap (for port 7777) is:
7777/udp open unreal Unreal Tournament 2004 game server
nmap -sU -sV -p <port(s)> <target>nmap -sS -sV -p <port(s)> <target>| Game | Protocol | Port(s) |
|---|---|---|
| Quake 1 | UDP/TCP | 26000 |
| war 2 combat | UDP/TCP | 6112 |
| Quake live | UDP/TCP | 27960 |
| Worms armageddon | TCP | 17011 |
| UT99 | UDP | 7777-7779 |
| Empire earth | UDP/TCP | 33334-33336 |
| Jazz Jackrabbit 2 | UDP/TCP | 10052-10054 |
First of all, there are unofficial patches ( see https://ut99.org/ ) , which you need to download in order to see the list of servers.
And then during hosting, there is a server.log file, which told me that these old servers don't existed yet anymore. So I had to update UnrealTournament.ini in order to copy the newer server lists from Default.ini
So there is a patch available, called jj2+ (see https://www.jazz2online.com/jcf/showthread.php?t=19489 ).
This is different from Jazz² Resurrection (thought that might work as well, I haven't messed with it).
Anyways, If you use GOG Galaxy, make sure that instead of manually downloading it (which does work for letting a friend try it out), you change the config to use the JJ2+ mod, which by default it does not. And so if you locally install the JJ2+ mod, GOG galaxy will be like: Oh, hey, the version you've just installed is not the same version according to your settings, and thus it will revert it instantly back to the regular (worse) version.
You can do this by clicking on the settings icon right of play button -> Manage Installation -> Configure -> under installation: set Beta channels to JJ2+ Mod.
Look at co-optimus.com https://www.co-optimus.com/system/13/classic.html# (specific link, but you can search however you want). Filter, System PC, online co-op, add co-op campaign if you want, click it, find games. Single click on release date to sort from oldest to newest, then scroll through all of the TBD pages, like page 17 or something, and then you see things in a good way.