Help with port forwarding for a multiplayer mission?

[pm_me_youngs_modulus]

So I'm trying to set up my port forwarding so that I can host some MP mission with friends but I can't seem to get the forwarding correct so that they can access the mission.

I so far set up:

1. Protocol as TCP-UDP.
2. External host as the IP address displayed in the DCS MP launch screen.
3. External port as 10308.
4. Internal host as my static IP address.
5. Internal port as 10308.
6. Firewall is set to allow DCS public and private access.

If I load the mission I can get into it but for anyone trying to connect it says "server offline".  I'm thinking maybe the internal port should be different than the external port but I'm not sure and I couldn't really find anything through google that addresses my specific situation.

Does anyone with experience in this have any ideas as to what I'm forgetting/messing up?