Dead Space 3: How to Fix COOP Connection Issue

According to my observations, this problem mostly occurs with old or cheap routers, buying a new one (most likely) can solve the problem without changing the router settings, but if you don’t want to change your router, you can do the following:

1. Open a Command Prompt and enter the ipconfig command.

2. Find the adapter that has the line Connection-specific DNS suffix: Home. After that, copy your IPv4 address.

3. Go to the router’s homepage, such as 192.168.1.1 for Tenda routers, and open its settings.

4. Find the DMZ Host option and paste the IPv4 address you copied.

5. Find NAT, then click the add button and write the following. Use your own IPv4 address for this:

Port start: 8080, port end: 8080 and ip.
TCP/UPD protocol (or just TCP).

6. Find NAT Port-forwarding (or something similar) and write the following:

Switch: Port start: 8080, port end: 8080.
Open: Port start: 8080, port end: 8080.
TCP/UPD protocol (or just TCP).

7. Find UnPnP and enable it.

This issue should be resolved at this point. I recommend that you disable the DMZ Host feature and remove the port forwarding columns after you finish the game for security reasons.