Help me see this code string rpc.

I want thus.

1.if client or inputusername no runing. server will no show string of outputusername in server or outputusername will = "";
2. if 1 Impractical. I want code check ip client connecting in server if client connecting server will show ip of client but client disconnect. server will no show ip in server

In other words i will do system online if client connecting in server will show username of client

---server---
public int Port = 25001;
public int num = 10;

public string outputusername = "";

public NetworkView nView;
public NetworkPlayer player;

void Start() {
nView = GetComponent<NetworkView>();
}

void OnGUI()
{
if(Network.peerType == NetworkPeerType.Disconnected)
{
if(GUI.Button(new Rect(100,100,100,25),"Start Server"))
{
bool useNat = !Network.HavePublicAddress();
Network.InitializeServer(num,Port,useNat);
}
}
if(Network.peerType == NetworkPeerType.Server)
{
GUI.Label(new Rect(100,100,100,25),outputusername);
}
}

[RPC]
void TestCheck(string username)
{
if(Network.isServer)
{
outputusername = username;
}
}
---------

---client---
public string IP = "192.168.1.2";
public int Port = 25001;
public string inputusername = "";

public NetworkView nView;
public NetworkPlayer player;

void Start() {
nView = GetComponent<NetworkView>();
}

void Update(){
if(Network.peerType == NetworkPeerType.Client){
nView.RPC("TestCheck",RPCMode.Server,inputusername);
}
}
void OnGUI()
{
if(Network.peerType == NetworkPeerType.Disconnected)
{
if(GUI.Button(new Rect(100,100,100,25),"Start Client"))
{
Network.Connect(IP,Port);
}
}
if(Network.peerType == NetworkPeerType.Client)
{
inputusername = GUI.TextArea(new Rect(100,75,110,25),inputusername);
}
}
[RPC]
void TestCheck(string username){}
---------