Winsock: "Connection is forcefully rejected" error

[Disiance]

I have written two programs, a client and server program. The client connects to the server, the server sends data and then closes the connection, then goes back to listen for more connections. The client connects fine, and everything goes like it should, but when I try to connect again (without resetting the server) I get a "Connection is forcefully rejected" error. Why? The server's state is 2 (listening).

Disiance

[Wokawidget]

I have moved this thread to the general VB Questions.

Can you post your code, that may give people a better idea.

Woof

[Disiance]

Server Code

Private Sub Form_Load()
    Set WinSCK = New Winsock
    WinSCK.LocalPort = 2890
    WinSCK.Listen
End Sub
Private Sub Form_Unload(Cancel As Integer)
    WinSCK.Close
End Sub
Private Sub WinSCK_DataArrival(ByVal bytesTotal As Long)
    MsgBox bytesTotal
End Sub
Private Sub WinSCK_ConnectionRequest(ByVal requestID As Long)
    WinSCK.Close
    WinSCK.Accept requestID
    WinSCK.SendData "P 1190"
    DoEvents
    WinSCK.Close
    Do Until WinSCK.State = 0
        DoEvents
    Loop
    WinSCK.Listen
End Sub

[Disiance]

Client Code (Right now its just a server testing program, so nothing's automated)

Private Sub Command1_Click()
    WinSCK.RemoteHost = "127.0.0.1"
    WinSCK.RemotePort = 2890
    WinSCK.Connect
    Do Until WinSCK.State = 7
      DoEvents
    Loop
End Sub
Private Sub Command2_Click()
    WinSCK.Close
    Do Until WinSCK.State = 0
        DoEvents
    Loop
    End
End Sub
Private Sub Command3_Click()
    WinSCK.SendData "Test"
End Sub
Private Sub Command4_Click()
    MsgBox WinSCK.State
End Sub
Private Sub Form_Unload(Cancel As Integer)
    WinSCK.Close
    End
End Sub
Private Sub WinSCK_DataArrival(ByVal bytesTotal As Long)
    Dim MyData As String
    WinSCK.GetData MyData
    MsgBox MyData
End Sub
Private Sub WinSCK_Error(ByVal Number As Integer, Description As String, ByVal Scode As Long, ByVal Source As String, ByVal HelpFile As String, ByVal HelpContext As Long, CancelDisplay As Boolean)
    MsgBox Description
    MsgBox "Closing Winsock"
    WinSCK.Close
End Sub

[joe_oej]

Are you sure its closed? Maybe the loop is still going when it tries to connect. Sometimes after closing a connection i've noticed that it sits there on "Waiting to Close" (state: 9). I usually implement a timer checking all winsock controls for that state and calling the .Close method again if detected.

Just a thought..

[Disiance]

That's why I put in the Command4 button (I know, I should name the things, but its just a testing app so ). It tells me the state of the winsock, and the state is 0 (closed). I know the server state is 2 (listening) because I have a button on that one too that tells me the state.

Disiance

[Disiance]

Oh, also I know its a problem with the server because when I close it and reopen it the client can connect again. Then I have to reset it again, and again, and again, but each time I reopen it the client can connect (without resetting the client).

Disiance

[Disiance]

anyone??

Disiance

[dglienna]

maybe it needs time to process the Close event before accepting data? I notice that you have two ways to do this already, but nothing after the first line of the WinSCK_ConnectionRequest

[HellRaider]

That happend to me once but it was because of my firewall, its just a thought but maybe it may help.

[Disiance]

Well, I tried adding the other Do Loop in, didn't help. I thought about it being my firewall but I'm bypassing it (I use 127.0.0.1 for IP right now). I have even altered the code so that after a connection the server would unload and reload the connection form, didn't help.

Disiance

[BuggyProgrammer]

Move this (server code):

DoEvents
WinSCK.Close
Do Until WinSCK.State = 0
DoEvents
Loop
WinSCK.Listen

to the Winsock_SendComplete event (removing the do loop and the doevents.

You don't need this in the client code:
Do Until WinSCK.State = 7
DoEvents
Loop

[Disiance]

Originally posted by BuggyProgrammer
Move this (server code):

DoEvents
WinSCK.Close
Do Until WinSCK.State = 0
DoEvents
Loop
WinSCK.Listen

to the Winsock_SendComplete event (removing the do loop and the doevents.

You don't need this in the client code:
Do Until WinSCK.State = 7
DoEvents
Loop

Ok, havn't tried it so I'm not sure it works, but eventually I do want to send more than one message to the client before disconnecting, should I add a counter to count the number of messages sent?

Disiance

[baja_yu]

When does the error occur exactly? Does it connect at all?
It may be that you have a Firewall which is not allowing the app to make a connection. That situation would produce a "...connection forcefully rejected" error.

[Disiance]

Originally posted by baja_yu
When does the error occur exactly? Does it connect at all?
It may be that you have a Firewall which is not allowing the app to make a connection. That situation would produce a "...connection forcefully rejected" error.

The client connects just fine, receives the data, and then disconnects. I get the error when it tries to connect a 2nd time. The only way to fix it that I've found is to close the server program and start it again.

Disiance

[beic]

The client connects just fine, receives the data, and then disconnects. I get the error when it tries to connect a 2nd time. The only way to fix it that I've found is to close the server program and start it again.

Disiance

I know it's an old post, but I got the same error with same description.

Did you manage to solve it?

Thanks!

[SmUX2k]

I know it's an old post, but I got the same error with same description.

Did you manage to solve it?

Thanks!

As their last activity (check their profile) was 10 years ago, you probably won't get a response. The right thing to have done here is starting a new post describing your own issue and referencing this one so people know you've looked here.

[wqweto]

I know it's an old post, but I got the same error with same description.

Did you manage to solve it?

Thanks!

The server implementation in this thread is bonkers. You don’t accept incomming connections on the listening socket they do.

Better start a new thread titled “How to write simple TCP server using Winsock control - samples” or similar.