[RESOLVED] Code to Extract TCP Client's IP Address

[Vladamir]

The TCP Listener project is starting to gel. And one of the things I did was to find some code which will determine the IP address of the client sending in the stream. I could swear that this worked yesterday.

Dim ipend = System.Net.Dns.GetHostEntry(System.Net.Dns.GetHostName()).AddressList(0).ToString()

But today it's assigning the IP address of the machine which my TCP Listener is running on instead of the IP address of the client sending in the data. I really thought I saw this work successfully yesterday. Am I on drugs or what?

[dbasnett]

Are you using TCPClient? If so the client remote endpoint should have the ip address already.

[make me rain]

even though i m not much conversant with http, i have some important links, i think which may help you

(1) http://www.4guysfromrolla.com/articles/071807-1.aspx
(2) http://www.vbforums.com/showthread.p...-get-client-IP
(3) http://www.vbforums.com/showthread.p...t=#post4373481
(4) http://www.vbforums.com/showthread.p...t=#post4366907

[formlesstree4]

What you're doing, Vladimir, is getting the host machine's (local, sometimes) IP address. I recommend doing a quick search for what you want, and I actually found a few different articles that would probably be very helpful to you!


EDIT: Reading the MSDN page on the TcpClient reveals the underlying Client Property which is actually a Socket which contains a RemoteEndPoint property which is defined as:

The EndPoint with which the Socket is communicating.

You can cast the EndPoint as an IPEndPoint and use the Address property to get the IP Address!

[Vladamir]

formlesstree4,

That second link to codeproject was the actual code I found yesterday in my search. But there were some comments by other users at the bottom of that page where one guy said he did it the hard way. All that code could be written with one line. And I must have been dreaming because I was certain that yesterday I used this and it was showing the IP address of the machine which sent in the data stream. Even when I tested it from a remote machine outside if this lan it gave a weird IP address of one of the external routers at this place which must be owned by UC Fresno. I guess I was smoking something because today it's only giving up the IP of the machine my program is running on.

OK, so I'm trying to understand what you wrote there...

Dim s as Socket
Dim ipend = (IPAddress.Parse(CType(s.RemoteEndPoint, IPEndPoint).Address.ToString()))

Sorry to be so dense, this is what it seems to want to get the next line working with s. But then when I

lvi.SubItems.Add(ipend)

I get a very long error about strings conversion again.

[formlesstree4]

formlesstree4,

That second link to codeproject was the actual code I found yesterday in my search. But there were some comments by other users at the bottom of that page where one guy said he did it the hard way. All that code could be written with one line. And I must have been dreaming because I was certain that yesterday I used this and it was showing the IP address of the machine which sent in the data stream. Even when I tested it from a remote machine outside if this lan it gave a weird IP address of one of the external routers at this place which must be owned by UC Fresno. I guess I was smoking something because today it's only giving up the IP of the machine my program is running on.

OK, so I'm trying to understand what you wrote there...

s.Connect(lep)
(CType(s.RemoteEndPoint, IPEndPoint).Address.ToString()))

Sorry to be so dense, but I cannot translate this. I've tried lots of stuff, but I cannot recreate this code in my project, it keeps assigning what I type to something else.

1) What have you tried?
2) What actual is being assigned?
3) The 2nd line is just doing a conversion and not actually assigning it to any variable.

[Vladamir]

Sorry about that, I'm making so many changes on the fly. The above post shows my latest corrections to my otherwise ramblings of today. Thanks again for your assistance and patience in this.

[formlesstree4]

Can you post the error message?

[Vladamir]

Overload resolution failed because no accessible 'Add' can be called with these arguments:
'Public Function Add(text As String) As System.Windows.Forms.ListViewItem.ListViewSubItem': Value of type 'System.Net.IPAddress' cannot be converted to 'String'.
'Public Function Add(item As System.Windows.Forms.ListViewItem.ListViewSubItem) As System.Windows.Forms.ListViewItem.ListViewSubItem': Value of type 'System.Net.IPAddress' cannot be converted to 'System.Windows.Forms.ListViewItem.ListViewSubItem'.

It's part of this code, which most is working successfully, so far. The blue code is the new code I added, the red one is the offending line.

Option Strict On
Imports System.Net.Sockets
Imports System.Threading
Imports System.IO
Imports System.Net

Public Class Form1
    Dim Listener As New TcpListener(81)
    Dim Client As New TcpClient
    Dim Message As String = ""

    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
        Dim ListThread As New Thread(New ThreadStart(AddressOf Listening))
        ListThread.Start()
    End Sub

    Private Sub Listening()
        Listener.Start()
    End Sub

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick

        Dim vWord() As String
        Dim lvi As ListViewItem

        If Listener.Pending = True Then
            Message = ""
            Client = Listener.AcceptTcpClient()
            Dim Reader As New StreamReader(Client.GetStream())
            While Reader.Peek > -1
                Message = Message + Convert.ToChar(Reader.Read()).ToString
            End While

            Dim s As Socket
            Dim ipend = (IPAddress.Parse(CType(s.RemoteEndPoint, IPEndPoint).Address.ToString()))

            vWord = CType(ParseData(Message), String())

            lvi = New ListViewItem(Now.ToString("ddd   MM/dd/yyyy   hh:mm tt "))
            ListView1.Items.Add(lvi)
            'lvi.SubItems.Add(vWord(1))
           
            lvi.SubItems.Add(ipend)

            lvi.SubItems.Add(vWord(10))
            lvi.SubItems.Add(vWord(1))
            lvi.SubItems.Add(vWord(2))


        End If
    End Sub

    Private Function ParseData(ByVal Message As String) As Array

        Message = Message.Substring(InStr(Message, "="))

        Dim words As String() = Message.Split(CChar("&"))
        Dim word As String

        Dim upperBound As Integer = words.GetUpperBound(0)
        Dim vWord(upperBound) As String
        For i = 0 To upperBound
            vWord(i) = words(i).Substring(InStr(words(i), "="))
        Next
        Return vWord

    End Function

[formlesstree4]

ipend is implied to be Object because you didn't declare it with an As statement:

Dim ipend As String = (IPAddress.Parse(CType(s.RemoteEndPoint, IPEndPoint).Address.ToString())).ToString()

[Vladamir]

Thanks again formlesstree4. I guess I don't understand all this typing stuff yet. I edited the line as you have shown but now it's giving me "Object reference not set to an instance of an object." error message. I'm clueless and again thanks for your patience. If I can get this working it will be fine and another item I've learned the hard way.

[formlesstree4]

Thanks again formlesstree4. I guess I don't understand all this typing stuff yet. I edited the line as you have shown but now it's giving me "Object reference not set to an instance of an object." error message. I'm clueless and again thanks for your patience. If I can get this working it will be fine and another item I've learned the hard way.

What on earth...where's the error happening this time? I'm just glancing over the code quickly and nothing stands out. Do me a favor, and go to the TOP of the code page and add the following lines (before any Import statements and Class declarations):

Option Strict On
Option Explicit On

Those should literally be Lines 1 and 2.

EDIT: I see the problem:

Dim s As Socket

That's not correct at all.

You should be pulling from the Client Object you declared earlier:

Client = Listener.AcceptTcpClient()

Right there. Try doing this instead:

Dim ipend As String = (IPAddress.Parse(CType(Client.Client.RemoteEndPoint, IPEndPoint).Address.ToString())).ToString()

[Vladamir]

Thanks. That's got it. I was just about to propose that it must have something to do with s. When I tried to type in Client before it would not take it, that is only Client. But when I typed in Client.Client it took it and now all is well. Can't thank you enough.

[formlesstree4]

Thanks. That's got it. I was just about to propose that it must have something to do with s. When I tried to type in Client before it would not take it, that is only Client. But when I typed in Client.Client it took it and now all is well. Can't thank you enough.

Not a problem. If all is good, you should mark the thread as resolved. If you don't know how, you go up to the Thread Tools menu (at the top of the page), and click the mark the topic as resolved button.