Posted June 07, 2017
Copied from a D:OS topic in the Larian forum:
The game's client will try to assign a port in the range 23243-23252, the server in the range 23253-23262. While forwarding these ports on your gateway might help, there is no guarantee the gateway will assign an external port in this range when connecting to our NATPunch server (this is the port that will be assumed to be the external port for all connections).
I did have the game set to public, though changed it after starting the game (from invite only). Galaxy had an update notification I didn't see until later, as well, which may have been a factor.
The game's client will try to assign a port in the range 23243-23252, the server in the range 23253-23262. While forwarding these ports on your gateway might help, there is no guarantee the gateway will assign an external port in this range when connecting to our NATPunch server (this is the port that will be assumed to be the external port for all connections).
I did have the game set to public, though changed it after starting the game (from invite only). Galaxy had an update notification I didn't see until later, as well, which may have been a factor.