How to get exact ip address of local machine in ASP.Net

i am writing this code in asp.net with C#. First you have to import these namespace :

using System.Net;
using System.Net.Sockets;

C# 

protected void Page_Load(object sender, EventArgs e)
    {
        if (!this.IsPostBack)
        {            
            IPAddress[] localIPs = Dns.GetHostAddresses(Dns.GetHostName());
            foreach (IPAddress addr in localIPs)
            {
                if (addr.AddressFamily == AddressFamily.InterNetwork)
                {                   
                    string ipAddress = addr.ToString();                    
                    lblIpAddress.Text = ipAddress;
                }
            }
        }
    }

Now you can use ipAddress to validate user in your query