Introduction:
In this article,i am going to explain about how to authenticate web service into a particular client machine without using
userid/password (stored in database).

Main:

Normally we know in windows/password based authentications we are using ip addess for validating windows account.
so here also i tried the same ip address approach for authenticating particular client machine.

Steps Involved,

1.Store Client machine ip in config file,
2.In Auth header i added extra field ‘ip’ for validating client machine ip address,
3.In client side,i added the extra coding for getting ip address using system.net namespace.

public class AuthHeader : SoapHeader
{
public string Username;
public string Password;
public string ip;

}

Web service sample code:

using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Services; using System.Web.Services.Protocols;   namespace netprogWSex { /// <summary> /// Summary description for Service1 /// </summary> [WebService(Namespace = "http://tempuri.org/")] [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)] [System.ComponentModel.ToolboxItem(false)] // To allow this Web Service to be called from script, using ASP.NET AJAX, uncomment the following line. // [System.Web.Script.Services.ScriptService] public class Service1 : System.Web.Services.WebService { public AuthHeader Authentication;   [SoapHeader("Authentication")] [WebMethod] public string WelcomeString() { if (Authentication.ip == "124.123.129.119") { return "Welcome Client machine"; } else { if (Authentication.Username == "test" && Authentication.Password == "test") { return "I am Web Method";   }   else { return "You don't have access"; } }   //return "ends"; }   }   public class AuthHeader : SoapHeader { public string Username; public string Password; public string ip;   } }

Client sample code:

using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.ComponentModel; using System.Net;   namespace WsClient { class Program { static void Main(string[] args) { ServiceReference2.AuthHeader authentication = new WsClient.ServiceReference2.AuthHeader(); authentication.Username = ""; authentication.Password = "";   string strhost = Dns.GetHostName(); string ipaddress1=null;   //IPAddress[] addr = Dns.GetHostByName(strhost);   IPHostEntry Local_Entry = Dns.GetHostByName(strhost); IPAddress[] addr = Local_Entry.AddressList;   for (int i = 0; i < addr.Length; i++) { ipaddress1 = addr[i].ToString(); }   authentication.ip = ipaddress1;   WsClient.ServiceReference2.WelcomeStringRequest obj = new WsClient.ServiceReference2.WelcomeStringRequest(); obj.AuthHeader = authentication;   WsClient.ServiceReference2.WelcomeStringResponse objres = new WsClient.ServiceReference2.WelcomeStringResponse();   WsClient.ServiceReference2.Service1SoapClient ong = new WsClient.ServiceReference2.Service1SoapClient(); Console.WriteLine(ong.WelcomeString(authentication)); Console.ReadLine();   } } }

Conclusion:
Hope this helps,
Happy Coding.