It no longer works with changing Windows firewall rules. It might be possible via processing packets realtime, but I don't have time to investigate.
So here's the notice that this doesn't work and I have no plans to try and fix it, sorry.
A tool to setup your GTA5 firewall rules easily. Adding IPs to your whitelist enables your friends to stay in your session.
- Download the latest release and extract all files.
- Inside the folder start the .EXE as administrator.
- Start the program with Windows firewall enabled, then press yes on the UAC prompt.
- Click "Activate Rules".
- Join GTA online.
- Start the program with Windows firewall enabled, then press yes on the UAC prompt.
- Click "Activate Rules".
- Join GTA online.
- Click "Deactivate Rules" and invite your friends.
- If they're all there click "Activate rules" again.
Note: you don't need to add your own IP Address.