NetworkManager

The NetworkManager is a script component handling all your Networking related settings, your Networked Prefabs and your registered scene names. A Transport component is needed on the same GameObject. it's responsible for handling IP adresses and additional settings.

Starting a Server, Host, or Client

The NetworkManager allows you to start/stop the Networking. It provides the same functions for Server, Host and Client.

The Host functions as Server and Client simultaneously:

NetworkManager.Singleton.StartServer();      //or
NetworkManager.Singleton.StartHost();        //or
NetworkManager.Singleton.StartClient();

note

When starting a Server or joining a running session as client, the NetworkManager will spawn a "Player Object" belonging to that Player. You can choose which Prefab shall be spawned as "Player Object" in the NetworkManager Component under NetworkPrefabs. Simply tick the corresponding Default Player Prefab checkbox there.

Only the "Player Object" will return true for IsLocalPlayer on the corresponding machine, use IsOwner for non Player Objects instead.

Connecting

When Starting a Client, the NetworkManager uses the IP and the Port provided in your Transport component for connecting.

You can use different transports and have to replace the type inside the following GetComponent< > accordingly, but for UNET transport it looks like this:

NetworkManager.Singleton.GetComponent<UNetTransport>().ConnectAddress = "127.0.0.1"; //takes string
NetworkManager.Singleton.GetComponent<UNetTransport>().ConnectPort = 12345;          //takes integer

Disconnecting

Disconnecting is rather simple, but you have to remember, that you can't use the NetworkSceneManager for scene switching in most Disconnecting cases. As soon as you stop the Client, Server or Host you have to use UnityEngine.SceneManagement instead.

public void Disconnect()
{
    if (IsHost) 
    {
        NetworkManager.Singleton.StopHost();
    }
    else if (IsClient) 
    {
        NetworkManager.Singleton.StopClient();
    }
    else if (IsServer) 
    {
        NetworkManager.Singleton.StopServer();
    }
    
    UnityEngine.SceneManagement.SceneManager.LoadScene("MainMenu");
}

The only case where you can use the NetworkSceneManager for disconnecting, would be if the Server/Host switches back to MainMenu or similar for everyone and then Stopping the Server and all the Clients.

See NetworkSceneManager for more details.