Can't connect to Co-Op Server

[Brizzly]

Tried both connecting, and hosting using the new server creation tool within the sim, and neither me, nor my friend can connect to the other's server.  I can create a server that shows up in the list, and enter the mission myself, but my friend can't connect at all (both prior in the lobby, and during the mission).

 

The same issue happens when he creates a mission.  I can't connect, but he can start just fine on his end.

 

We are both able to connect to Coconut's normal server and play, though.

 

I've forwarded all the ports on my router, but still no dice.

[SCG_Schneemann]

You probably have a firewall or ISP server above your home setup. The only way I can get the Dserver to run reliably is to open a DMZ. My ISP apparently has a floating IP address above what I  see, so every time I either have to re set up my router, and keep my fingers crossed, or just DMZ it and forget about it. It's very finicky - lots of people have trouble with it.

[Brizzly]

Thanks for the reply, I’ve never run a DMZ (or heard of one in computing).  I’ll look into it.