Android Question FTPS (Net FTP library with .UseSSL)

[biometrics]

Has anyone been able to get FTPS (FTP with SSL) to work?

I can confirm it works with our FTP server (Ubuntu 12.04 with vsftpd) with the following clients:

• FileZilla Client - configured "Explicit FTP over TLS"
• VB6 and the Chilkat FTP2 ActiveX - configured ".AuthTls = 1" (AUTH SSL) & ".Ssl = 0" (not using implicit SSL connection)
• ES File Explorer on the same Android device as my B4A app - configured "encryption" = "explicit"

All the above using port 21.

When running Debug (rapid) or Release I just get the "Error" MsgBox (see code below). When running Debug (legacy) I get a Java error: "java.lang.Exception: Sub libftp_listcompleted signature does not match expected signature."

I have tested with a direct internet connection and via a correctly configured firewall.

I use the following test code. The only option I have is .UseSSL and the port number in the .Initialize call. I can't select implicit or explicit. I've tried setting .UseSSL before and after .Initialize.

When we enable dual SSL and non-SSL modes on the FTP server then the code runs.

Can anybody help me please?

Sub Process_Globals
   Dim libFTP As FTP
   Dim libContinueTimer As Timer

   Dim lCurrentState As Long
 
   Dim conStateIdle As Long
   Dim conStateConnecting As Long
   Dim conStateConnected As Long
   conStateIdle = 0
   conStateConnecting = 1
   conStateConnected = 2
End Sub

Sub Globals
End Sub

Sub Activity_Create(FirstTime As Boolean)
  lCurrentState = conStateIdle
 
  libContinueTimer.Initialize("libContinueTimer", 1)
  libContinueTimer.Interval = 1
  libContinueTimer.Enabled = True
End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Sub libContinueTimer_Tick
   libContinueTimer.Enabled = False
 
   Select Case lCurrentState 
   Case conStateIdle
     lCurrentState = conStateConnecting
     libFTP.Initialize("libFTP", "xxx", 21, "xxx", "xxx")
     libFTP.UseSSL = True
     libFTP.PassiveMode = True 
     libContinueTimer.Enabled = True
   Case conStateConnecting
     libFTP.List("/")
   Case conStateConnected
     Msgbox("Ok", "FTPS")
     ExitApplication
   End Select 
End Sub

Sub libFTP_ListCompleted(ServerPath As String, Success As Boolean, Folders() As FTPEntry, Files() As FTPEntry)
  Dim lIndex As Long
  Dim lFileCount As Long

  If Success Then
    lFileCount = Files.Length
   
     For lIndex = 0 To lFileCount - 1
       Log(Files(lIndex).Name)
     Next
   
     lCurrentState = conStateConnected
     libContinueTimer.Enabled = True
   Else
     Msgbox("Error", "FTPS")
     ExitApplication
  End If
End Sub

 

[Erel]

This is a strange error. Do you get the same error if you try to download a file?

 

[biometrics]

Hi Erel,

I had both the Net and NetExtras libraries selected. By unselecting NetExtras that error was resolved. I now get the following in the ListCompleted event with Log(LastException):

(SSLProtocolException) javax.net.ssl.SSLProtocolException: SSL handshake aborted: ssl=0x2cc510: Failure in SSL library, usually a protocol error
error:140770FC:SSL routines:SSL23_GET_SERVER_HELLO:unknown protocol (external/openssl/ssl/s23_clnt.c:683 0x401b4cc3:0x00000000)

 

[Erel]

It seems like your server uses a protocol not supported by the device.

 

[biometrics]

Hi Erel,

When I use ES File Explorer on the device to our FTP server it works fine though ...

 

[Erel]

Is this server accessible over the internet?

 

[biometrics]

Yes, it's a cloud server at Rackspace. Running Ubuntu 12.04 and vsftpd.

 

[Erel]

If you like you can send me the server details in a private message and I'll test it.

 

[biometrics]

Thanks Erel, shall I email the test project to support@basic4ppc.com? It has the logins in the code.

 

[DonManfred]

yes, that´s erels email

 

[Erel]

I didn't receive it. If the project is larger than 6mb then it might have been blocked. In that case please send it as a Dropbox (or similar) link.

 

[biometrics]

Just sent it now. Thanks.

 

[rbw152]

Was there any solution to this? I am experiencing the exact same problem. Thanks.

 

[DonManfred]

As always:
Please create a NEW thread for YOUR question. Posting to an 4 year old thread is the wrong way to get help.