Before we can open ports for BYOND, we need to set the port that BYOND will be hosting on. Here is a brief walkthrough on how to do that. Go ahead and open up Dream Seeker.
Load the game that you want to host. Once the game is loaded the Host button in the lower right of your screen shot light up. Click that button and you should see the screen above. Enter the port you want to host on into the Port box. It doesn't really matter what port you choose, but remember it because it is the port you will need to open. Please enter the port you chose into the box below.
Click the Security button near the top of the page.
Click the Application Monitor button near the left of the page.
We will list a series of lines here that will show you exactly how to setup Comodo Firewall's firewall for BYOND Dream Seeker Host. Go ahead and enter the settings shown below into the Network Control Rule menu.