Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Socket Reuse Issue

Posted on 2010-11-10
4
Medium Priority
?
940 Views
Last Modified: 2012-05-10
In the following code sample, I am explicitely setting a local endpoint for tracking purposes and then sending out a request.  While this works without issue the first time through, if I run the program again too quickly, I recieve the following exception:

System.Net.Sockets.SocketException: Only one use of each socket address (protocol/network address/port) is normally permitted

As you can see, I am closing out the connection in the Finally block but that does not appear to make a difference.  If you comment out the tester.Bind line you never get this error.

Can somebody please help?
Socket tester = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
            IPEndPoint thisEnd = new IPEndPoint(IPAddress.Any, 9736);
            tester.Bind(thisEnd);
            tester.Ttl = 255;

            try
            {
                tester.Connect(IPAddress.Parse("173.194.35.104"), 80);
                tester.Disconnect(true);
            }
            catch (Exception exc)
            {
                Console.WriteLine("Error with TCP Test:\n" + exc.ToString());
            }
            finally
            {
                if (tester != null && tester.Connected)
                {
                    tester.Disconnect(true);
                }
                if (tester != null)
                {
                    tester.Close();
                }
            }

Open in new window

0
Comment
Question by:ktola
  • 2
  • 2
4 Comments
 
LVL 75

Accepted Solution

by:
käµfm³d   👽 earned 2000 total points
ID: 34108242
From http://blogs.msdn.com/b/dgorti/archive/2005/09/18/470766.aspx :

When a connection is closed, on the side that is closing the connection the 5 tuple
{ Protocol, Local IP, Local Port, Remote IP, Remote Port} goes into a TIME_WAIT state for 240 seconds by default.
0
 

Author Comment

by:ktola
ID: 34108294
Yeah - I read that and then tried to change the Registry setting (actually added in the DWORD as it did not exist) but that did not change anything.  I just modified the code as follows and, for some reason, this appears to be working on the same port every time.
Socket tester = null;
            int startPort = 9729;
            IPEndPoint thisEnd;
            bool haveEndPt = false;

            while (!haveEndPt)
            {
                try
                {
                    tester = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
                    tester.ExclusiveAddressUse = false;
                    tester.Ttl = 255;
                    startPort += 1;
                    if (startPort > 9750)
                    {
                        haveEndPt = true;
                        throw new Exception("Unable to connect on any port from 9730 to 9750");
                    }
                    thisEnd = new IPEndPoint(IPAddress.Any, startPort);
                    tester.Bind(thisEnd);
                    haveEndPt = true;
                    Console.WriteLine("The selected TCP Handshake port was: " + startPort.ToString());
                    tester.Connect(IPAddress.Parse("173.194.35.104"), 80);
                    tester.Disconnect(true);
                }
                catch (SocketException sockX)
                {
                    //Console.WriteLine(sockX.ToString());
                }
                catch (Exception exc)
                {
                    Console.WriteLine("Error with TCP Test:\n" + exc.ToString());
                }
                finally
                {
                    if (tester != null && tester.Connected)
                    {
                        tester.Disconnect(true);
                    }
                    if (tester != null)
                    {
                        tester.Close();
                    }
                }
            }

Open in new window

0
 

Author Comment

by:ktola
ID: 34108327
In playing around with the code, it appears that the following line:
tester.ExclusiveAddressUse = false;

Actually overcomes the issue and allows for multiple requests on the same connection.  I also had to make sure that the Disconnect was set to true:
tester.Disconnect(true);
 
0
 
LVL 75

Expert Comment

by:käµfm³d 👽
ID: 34108329
Did you reboot the system after changing the registry?
0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Entity Framework is a powerful tool to help you interact with the DataBase but still doesn't help much when we have a Stored Procedure that returns more than one resultset. The solution takes some of out-of-the-box thinking; read on!
Performance in games development is paramount: every microsecond counts to be able to do everything in less than 33ms (aiming at 16ms). C# foreach statement is one of the worst performance killers, and here I explain why.
Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an anti-spam), the admin…
Want to learn how to record your desktop screen without having to use an outside camera. Click on this video and learn how to use the cool google extension called "Screencastify"! Step 1: Open a new google tab Step 2: Go to the left hand upper corn…

886 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question