Feel free to ask any question you may have related to this right here.

To be able to host online games in Bloody Trapland, you will need to open/forward port 6883 if you're behind a firewall/router.
How you do this varies depending on your OS/Router/Firewall.

Here is a step by step tutorial for windows.

• Make sure your ports are opened.
  1. Open your browser and type 192.168.0.1/192.168.1.1 to access your router. You will most likely need a username and password. (By Default both are 'admin')
  

  Note: If it isn't 192.168.0.1/192.168.1.1, just run Command Prompt in Windows (WindowsKey+R and type cmd or Start Menu > Accessories > Command Prompt).
  
  Afterwards, type in ipconfig, find your internet connection, and look for the Default Gateway. Typing that address in a browser should get you to your router.

  
  2. Go to port forwarding and open the port 6883.
  3. If your router doesn't reset automatically after applying the changes, do so.
  
  
• Make sure you have a static IP Adress.
  Probably under DCHP settings. It should be lower than your IPv4 adress. To find your IPv4 adress go to the start menu and type 'cmd', in the cmd type 'ipconfig' and hit enter. Example: If your IPv4 adress is 192.168.0.114 you could make your static IP 192.168.0.110
  
  
• Make sure you have made firewall exceptions
  1. Go to Control Panel>Windows Firewall>Advanced Settings>Rules for incoming connections>New rule
  2. Select Port>TCP>Specific>type '6883'>Allow connection
  3. Select Port>UDP>Specific>type '6883'>Allow connection
  4. Now do the same for outgoing connections
  
  
• Make sure your ports are not in use
  The port 6883 might be in use even without you knowing. If that is the case you won't be able to host a public server. A solution might be trying to portforward the port 7777, but this may not work. (This could be another port range this is just an example.) If you portforward another port do not forget to portforward the port and make the port a firewall exception.

A light-weight way to portforward using third-party software, works for some but not all.
https://steamproxy.net/sharedfiles/filedetails/?id=274366319

Hamachi Guide:
1: Download and install Hamachi https://vpn.net/
2: Inside hamachi, press the big start button.
3: A new window pops up, here you select a name for yourself.
4: Once connected, hamachi will established a virtual network for your computer, allow this as a homenetwork.
5: In hamachi Press "Create a new network", and set a name/password.
Give this name/password to your friends so they can join your network.
6: In hamachi, next to the Start button, you will see an ip like "5.78.81.94" for example, give this ip to your friends, they will need it to connect manually inside Bloody Trapland.

7: That's it, start Bloody Trapland, host a game, and let the mayhem begin!