Here is a list of the ports that need to be forwarded for Alien Swarm: Reactive Drop Server:
Alien Swarm: Reactive Drop Server - PC
- TCP: 27015
- UDP: 27015
Forward Ports for Alien Swarm: Reactive Drop Server

You may need to forward ports in your router when you use Alien Swarm: Reactive Drop Server. Forwarding ports is used to allow incoming connection requests from the internet to Alien Swarm: Reactive Drop Server.
Routers generally do not allow incoming connection requests from the internet. By forwarding a port you can overcome this limitation.
Before You Forward a Port
Before you can forward a port you need to know the following things:
- Your router's internal IP address.
- Your computer's internal IP address.
- The list of the TCP and UDP ports that you need to forward.
Locate Your Router's IP Address
The easiest way to locate your router's IP address is to run our free Router Detector utility. The software is part of our Network Utilities suite of tools and it is completely free to use.
Otherwise, you can follow our guide Find Your Router IP Address.
How To Forward Ports for Alien Swarm: Reactive Drop Server
You can use our Network Utilities software to automatically forward ports for you. Our Network Utilities software allows you to add port forwards and also remove them when you no longer need them to maximize your network security.
You can also choose to set up port forwards manually. The way to forward a port is:
- Log in to your router.
- Locate your routers port forwarding section.
- Type the IP address of your computer into the correct box in your router.
- Enter the TCP and UDP ports that you need to forward for Alien Swarm: Reactive Drop Server in the corresponding boxes in your router.
You probably will need to reboot your router for the changes to take effect.
You can choose your router from our list to see exactly how to forward ports for Alien Swarm: Reactive Drop Server:
List of Routers - Customized for Alien Swarm: Reactive Drop Server
Those are the steps for forwarding ports in your router for Alien Swarm: Reactive Drop Server.