Open a port with vb? [closed] - vb.net

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Can anyone please share a simple code for VB 2008 to open a port. I would like it to be just like utorrent how you can change the listening port for data transfer. thanks a lot if you can help me!

Answer 1

As Avner indicated, uTorrent is not simple code. If you'd like to do anything on that level, then you've got a lot to do.
Here is a simple sample socket program you can build on.
Imports System.Net
Imports System.Net.Sockets
Module Module1
Sub Main()
Console.WriteLine("Enter the host name or IP Address to connect to:")
Dim hostName = Console.ReadLine().Trim()
If hostName.Length = 0 Then
' use the local computer if there is no host provided
hostName = Dns.GetHostName()
End If
Dim ipAddress As IPAddress = Nothing
' parse and select the first IPv4 address
For Each address In Dns.GetHostEntry(hostName).AddressList
If (address.AddressFamily = AddressFamily.InterNetwork) Then
ipAddress = address
Exit For
End If
Next
' you will have to check beyond this point to ensure
' there is a valid address before connecting
Dim client = New TcpClient()
Try
' attempt to connect on the address
client.Connect(ipAddress, 80)
' do whatever you want with the connection
Catch ex As SocketException
' error accessing the socket
Catch ex As ArgumentNullException
' address is null
' hopefully this will never happen
Catch ex As ArgumentOutOfRangeException
' port must be from 0 to 64k (&HFFFF)
' check and ensure you've used the right port
Catch ex As ObjectDisposedException
' the tcpClient has been disposed
' hopefully this will never happen
Catch ex As Exception
' any other exception I haven't dreamt of
Finally
' close the connection
' the TcpClient.Close() method does not actually close the
' underlying connection. You have to close it yourself.
' http://support.microsoft.com/default.aspx?scid=kb%3Ben-us%3B821625
client.GetStream().Close()
' then close the client's connection
client.Close()
End Try
End Sub
End Module
Be aware that socket programming is quite complicated and you will have to thoroughly test your code for all edge cases.
Good luck!

Answer 2

uTorrent is anything but a "simple code". It's a complicated application with a lot of network logic going on beyond just opening a port and pushing bits in and out of it.
But your starting point for low-level communications handling would be the System.Net.Sockets namespace, which contains the Socket class. It allows low-level control such as opening a port, listening for connections and handling them yourself.
Here's a tutorial about Socket programming in VB.NET, but you'll probably find more information if you search for "C# Socket tutorial". C# syntax is a bit different than VB.NET, but it uses the same classes and the same concepts, so you'll probably be able to apply the lessons to your own code.