Tips & Tricks: Using System.Net To Write Better Connected Applications

1. Tips & Tricks: Using System.Net To Write Better Connected Applications Durgaprasad Gorti COML02 Test Lead Microsoft Corporation

2. Agenda • System.Net Tracing • Port Exhaustion • Sending Email with embedded objects • Encryption over Sockets

3. Before .NET Framework 2.0 Tracing • How can I debug my System.Net app?How can I see what’s going on the wire? What about SSL? Which process issued request? Which thread issued this request? What about loop back?

4. With System.Net Tracing Tracing • How can I debug my System.Net app?How can I see what’s going on the wire? Per process Shows thread IDs No recompile for app Works for loop back Shows SSL traffic App 2 App1 <Configuration> </Configuration> <Configuration> </Configuration> …POST http://...… …GET http://...… Log file Log file

5. Using System.Net Tracing

6. Port Exhaustion • I see SocketException: Only one usage of each socket address (protocol/network address/port) is normally permitted. How can I fix this? • Scenarios • Repeated authenticated web service calls to the same server • Authenticated/Unauthenticated calls with KeepAlive=false {protocol, local IP, local port, remote IP, remote port} enters TIME_WAIT state for 4 minutes by default ON ACTIVE CLOSE

7. Port exhaustion

8. Port Exhaustion • Recommendations • HKLM\System\CurrentControlSet\Services\Tcpip\Parameters • MaxUserPort - Dynamic Port range • Default 5000 • Max Value 65534 • Set the MaxUserPort to a higher value than 5000 • TCPTimedWaitDelay - How long a connection remains in TIME_WAIT state • Default 240 seconds • Range: 30-240 Seconds • You can set this to as low as 30 seconds

9. Port Exhaustion • Recommendations • ServicePoint.BindIPEndPointDelegate Req.ServicePoint.BindIPEndPointDelegate = new BindIPEndPoint(BindIPEndPointCallback); public static IPEndPoint BindIPEndPointCallback(ServicePoint servicePoint, IPEndPoint remoteEndPoint, int retryCount) { int port = Interlocked.Increment(ref m_LastBindPortUsed); //increment Interlocked.CompareExchange(ref m_LastBindPortUsed, 5001, 65534); if(remoteEndPoint.AddressFamily == AddressFamily.InterNetwork){ return new IPEndPoint(IPAddress.Any,port); } else{ return new IPEndPoint(IPAddress.IPv6Any,port); } }

10. Send/Receive – EMail • How do I use embedded objects in my email?

11. SMTP Mail

12. Send/Receive – Encryption Over Sockets • I use sockets. How can I authenticate and/or encrypt data over sockets? • Recommendations • NegotiateStream • Uses windows auth • SSLStream • Uses Certificates

13. Send/Receive – Encryption Over Sockets • I use sockets. How can I authenticate and/or encrypt data over sockets? server client “1234-5678-0000-1234” “1234-5678-0000-1234” Networkstream Networkstream socket socket “1234-5678-0000-1234”

14. Send/Receive – Encryption Over Sockets • I use sockets. How can I authenticate and/or encrypt data over sockets? client server “1234-5678-0000-1234” “1234-5678-0000-1234” AuthenticateAsClient  Negotiate/SSL stream Negotiate/SSL stream  AuthenticateAsServer Networkstream Networkstream “&*@a1!” socket socket

15. Send/Receive – Encryption Over Sockets • I use sockets. How can I authenticate and/or encrypt data over sockets? CLIENT Authenticated! Unauthenticated Stream AppStream = null; TcpClient client = new TcpClient(<server>, <port>); NetworkStream networkStream = client.GetStream(); NegotiateStream ns = newNegotiateStream(networkStream); ns.AuthenticateAsClient(); string s = "Hello From Client"; byte[] bytes = Encoding.ASCII.GetBytes(s); ns.Write(bytes, 0, bytes.Length); Stream AppStream = null; TcpClient client = new TcpClient(<server>, <port>); NetworkStream networkStream = client.GetStream(); string s = "Hello From Client"; byte[] bytes = Encoding.ASCII.GetBytes(s); networkStream.Write(bytes, 0, bytes.Length);

16. Send/Receive – Encryption Over Sockets • I use sockets. How can I authenticate and/or encrypt data over sockets? Server Unauthenticated Authenticated! Stream AppStream = null; TcpClient client = new TcpClient(server,port); NetworkStream networkStream = client.GetStream(); NegotiateStream ns = new NegotiateStream(networkStream); ns.AuthenticateAsServer();string client = ns.RemoteIdentity.Name; byte[] bytes = new byte[256]; int read = ns.Read(bytes, 0, bytes.Length); TcpListener Server = new TcpListener(<IP>, <Port>); Server.Start();TcpClient client = Server.AcceptTcpClient(); NetworkStream networkStream = client.GetStream();byte[] bytes = new byte[256]; int read = networkStream.Read(bytes, 0, bytes.Length);

17. Call to Action • Use System.Net 2.0 and take advantage of the new features • SMTP, FTP, Caching, SSL/Negotiate Stream • Provide feedback • dgorti@microsoft.com • chadmu@microsoft.com • mflasko@microsoft.com • New feature asks • nclasks@microsoft.com

18. Community Resources • Use msdn forums for questions and comments • http://forums.microsoft.com/msdn • All of my team hangs out on that forum so that is your best bet for System.Net questions • Blogs • http://blogs.msdn.com/dgorti • http://blogs.msdn.com/malarch • http://blogs.msdn.com/mahjayar • http://blogs.msdn.com/joncole • http://blogs.msdn.com/mflasko

19. Questions? dgorti@microsoft.com

20. © 2005 Microsoft Corporation. All rights reserved. This presentation is for informational purposes only. Microsoft makes no warranties, express or implied, in this summary.