Socket Connection

[Rusty]

I have opened a socket with NO server listening (as a test) and I still get a successful socket connection.

If Main.TCP.IPaddress <> "" Then    'we have defined a server, but it is not online
            Socket1.Close
            XferFile.Initialize
            Socket1.Initialize("Socket1")
            SetBufferSize(Socket1, ChunkSize)
            Socket1.Connect(Main.TCp.IPAddress, Main.TCP.Port, 0)
        End If

Sub Socket1_Connected (Successful As Boolean)
    If Successful = True Then
Log("Socket connected")
        Main.TCP.Connected = -1                        'tell the app we have a TCP server available
        MsgAcked = True
        WeAreConnected = True
'        N.SetInfo("Network", "TCP Connected! ", Main)    'let them know it is connected
        Astreams.Initialize(Socket1.InputStream,  Socket1.OutputStream, "AStreams")
        SendMsg(chnCommands,"MYID:~" & Main.version.SerialNo & "~" & Main.LicenseData.GroupCode & "~Version: " & Main.Version.NewVersion & "~" & _
                Main.CS.FacilityID & " " & Main.licensedata.Addr1 & " " & Main.LicenseData.City & ", " & Main.LicenseData.state)    'let them know who we are
    End If
End Sub

I receive the Log message socket connected even when nothing is listening.
How can i be getting a SUCCESS when there is nothing on the other end listening?
Thanks,

 

[Erel]

If the port was previously opened than the OS might still regard it as a valid port.

In that case it will fail when you try to send anything.

 

[Rusty]

How would the OS open the port?
The application starts, issues a StartService(TCPService); there is no listener anywhere (I've shut down the entire network) and the socket1.connected shows a successful connection.
Any ideas or suggestions?

 

[Erel]

The connected status comes from the native API. The OS might treat this port as an open port if it was opened before. However this is only an assumption.

 

[Rusty]

My client has two different TCP configurations installed.
1. The port address is 7890
2. The port address is 443

I recall seeing that ports under 2000 (or so) are reserved or could be a problem. If I am using 443, will this necessarily be a problem?
Thanks

 

[Erel]

You cannot open a port smaller than 1024 (with ServerSocket). However there is no problem with connecting to any external port.

 

[Rusty]

Is there any way to force the OS to close the port(s) or to detect that this is an OS port as opposed to one I open?
Thanks,
Rusty

 

[mc73]

As I've said in another thread, I am using arrays of sockets and streams, for two reasons: One, It's necessary for my app (many clients involved) and secondly, occasionally I'm facing some troubles with connections. My feel is (thought I don't like such expressions in programming) that somehow the os doesn't always handle connections perfectly. Perhaps you could try an array too? Another thing that I've just seen: Why are you setting 0 as a time limit? I remember, in a test I did, I had set a very small one, and the behavior was unpredictable in general.

 

[Rusty]

Thanks,
I saw your post with arrays of sockets etc. and will give that a try.
I guess abandoning sockets and astreams won't eat up too much resource, will it?
I saw the zero in my timeout earlier today and changed it to 3000ms. I even put in a 3 second delay after closing and no changes. The OS seems to leave the port open after it has be "closed" in the app.open comms

• communications work great
• shut down server comms
• Android app trys to recover
• port "connects" successfully (even though no server is out there)
• continues like it is connected...
• after a great while, it will give an Astreams_error
• if you restart the server, it will communicate again

Thanks,
Rusty