For your friend to see your game you have to have "Announce On Matchmaker" enabled in the settings page. This is enabled by doing the hosting test which in-turn enables Announce Allowed and Announce Host in your player file. If you ran the test and it failed, these will be disabled.
You will need to allow rfactor the access it requires (see the firewall Guide documentation in your rfactor/support folder).
After setting up your router/firewall with the required port access, run the hosting test on the settings page. If it fails, follow the instructions below:
Note that the network test cannot detect every possible network setup and thus may report that it cannot determine the status of your connection. In this case, do not use the network test and follow the instructions below:
- Open your multiplayer.ini file located in your rfactor/UserData/<playername> folder with a plain text editor such notepad (not a word processor).
- Find the following lines and set the values as shown below
Announce Allowed="1" // servers should pass the firewall test before being allowed to list on the matchmaker
Announce Host="1" // whether servers will attempt to register with the matchmaking service
- DO NOT ATTEMPT TO RUN THE NETWORK TEST AFTER SETTING THESE VALUES OR YOU WILL RESET THEM.
...Host your game
Also make sure your friends have "Concurrent Server Updates="1000"" (or higher) in their multiplayer.ini file in order to see more servers.