From their Github
Impostor is one of the first Among Us private servers, written in C#. There are no special features at this moment, the goal is aiming to be as close as possible to the real server, for now. In a later stage, making modifications to game logic by modifying GameData packets can be looked at.
You MUST use Port 22023 for the Master Server. To host multiple servers, please read Impostor Multiple Servers Documentation.
Ports required to run the server in a table format.
| Port | default |
|---|---|
| Game | 22023 |