Called on client during disconnection from server, but also on the server when the connection has disconnected.

When called on the client the connection was lost or you disconnected from the server. The NetworkDisconnection enum will indicate if the connection was cleanly disconnected or if the connection was lost. When called on the server the connection has successfully disconnected (after a call to Network.Disconnect).

	function OnDisconnectedFromServer(info : NetworkDisconnection) {
		if (Network.isServer) {
			Debug.Log("Local server connection disconnected");
		}
		else {
			if (info == NetworkDisconnection.LostConnection)
				Debug.Log("Lost connection to the server");
			else
				Debug.Log("Successfully diconnected from the server");
		}
	}

using UnityEngine;
using System.Collections;

public class Example : MonoBehaviour {
    void OnDisconnectedFromServer(NetworkDisconnection info) {
        if (Network.isServer)
            Debug.Log("Local server connection disconnected");
        else
            if (info == NetworkDisconnection.LostConnection)
                Debug.Log("Lost connection to the server");
            else
                Debug.Log("Successfully diconnected from the server");
    }
}

import UnityEngine
import System.Collections

public class Example(MonoBehaviour):

	def OnDisconnectedFromServer(info as NetworkDisconnection) as void:
		if Network.isServer:
			Debug.Log('Local server connection disconnected')
		elif info == NetworkDisconnection.LostConnection:
			Debug.Log('Lost connection to the server')
		else:
			Debug.Log('Successfully diconnected from the server')