Indicate if proxy support is needed, in which case traffic is relayed through the proxy server.

The proxy server is a solution to connectivity problems with servers as well as clients. When a machine has an non NAT punchthrough capable router his connectivity options are limited. A game cannot be hosted as nobody external can connect to him (only clients on the local network can). By using the proxy server the machine can be fully connectable but with the extra cost of having all traffic relayed through another server. A non NAT punchthrough capable client can connect to any server through the proxy server, as long as the proxy server is set up properly.

Unity Technologies does not provide a proxy server for public use, so to use this feature you will need to set up your own proxy server. Of course it is advisable to set up a proxy server with a public IP address and a lot of available bandwidth.

When running as a client, just enabling Network.useProxy is all you have to do. Connect to the server as usual with Network.Connect(). All traffic will be relayed through the proxy server. The servers external IP and internal IP still work as usual. So clients can connect to him directly without the proxy in case they are located on the same network.

When running as a server OnServerInitialized(NetworkPlayer) returns a NetworkPlayer structure which indicates what the game servers relayed IP/port is, i.e. what port the proxy server allocated to the game server. This is the IP/port others can use to connect to. When connecting to the server, the clients don't treat the server any differently than other servers. Technically speaking, they don't need to know at all that the game server is getting help from a proxy server.

When using the master server you can no longer only rely on the IP/port he registers for servers when using proxy support. The proxy server IP address and port which the server is using can be placed in the comment field of the data sent to the master server. A client which received host information from the master server can peek into the comment field and find out if he can use an alternative IP/port for that host.

IMPORTANT: You should never enable proxy support for both the server and the client connecting to him. Unexpected things are bound to happen.

	var imaserver: boolean;
	var serverIP: String;
	var serverPort: int;
	var serverUsesNAT: boolean;
	
	function Awake() {
		// Set custom proxy server address
		Network.proxyIP = "1.1.1.1";
		Network.proxyPort = 1111;
	
		if (imaserver)
			StartServerWithProxy();
		else
			ConnectToServerWithProxy();
	}
	
	function StartServerWithProxy() {
		Network.useProxy = true;
		Network.InitializeServer(2,25000, false);
	}
	
	function OnServerInitialized(player: NetworkPlayer) {
		if (Network.useProxy)
			Debug.Log ("Successfully started server with proxy support. We are connectable through "
				+ player.ipAddress + ":" + player.port);
	}
	function OnFailedToConnect(msg: NetworkConnectionError) {
		if (Network.useProxy && imaserver) {
			Debug.LogError("Failed to connect to proxy server: " + msg);
		}
	}
	function ConnectToServerWithProxy() {
		Network.useProxy = true;
		Network.Connect(serverIP, serverPort);
	}
	function OnConnectedToServer() {
		Debug.Log("Connected successfully to server");
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    public bool imaserver;
    public string serverIP;
    public int serverPort;
    public bool serverUsesNAT;
    void Awake() {
        Network.proxyIP = "1.1.1.1";
        Network.proxyPort = 1111;
        if (imaserver)
            StartServerWithProxy();
        else
            ConnectToServerWithProxy();
    }
    void StartServerWithProxy() {
        Network.useProxy = true;
        Network.InitializeServer(2, 25000, false);
    }
    void OnServerInitialized(NetworkPlayer player) {
        if (Network.useProxy)
            Debug.Log("Successfully started server with proxy support. We are connectable through " + player.ipAddress + ":" + player.port);
        
    }
    void OnFailedToConnect(NetworkConnectionError msg) {
        if (Network.useProxy && imaserver)
            Debug.LogError("Failed to connect to proxy server: " + msg);
        
    }
    void ConnectToServerWithProxy() {
        Network.useProxy = true;
        Network.Connect(serverIP, serverPort);
    }
    void OnConnectedToServer() {
        Debug.Log("Connected successfully to server");
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	public imaserver as bool

	public serverIP as string

	public serverPort as int

	public serverUsesNAT as bool

	def Awake() as void:
		Network.proxyIP = '1.1.1.1'
		Network.proxyPort = 1111
		if imaserver:
			StartServerWithProxy()
		else:
			ConnectToServerWithProxy()

	def StartServerWithProxy() as void:
		Network.useProxy = true
		Network.InitializeServer(2, 25000, false)

	def OnServerInitialized(player as NetworkPlayer) as void:
		if Network.useProxy:
			Debug.Log(((('Successfully started server with proxy support. We are connectable through ' + player.ipAddress) + ':') + player.port))

	def OnFailedToConnect(msg as NetworkConnectionError) as void:
		if Network.useProxy and imaserver:
			Debug.LogError(('Failed to connect to proxy server: ' + msg))

	def ConnectToServerWithProxy() as void:
		Network.useProxy = true
		Network.Connect(serverIP, serverPort)

	def OnConnectedToServer() as void:
		Debug.Log('Connected successfully to server')