[NET-408] problem connecting to ProFTPD with FTPES

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.2, 3.0
• Component/s: FTP

Environment

ProFTPD 1.3.3d on SUSE Linux Enterprise Server 10.1 32bit, Kernel 2.6.16.46-0.12-default (config file attached)
ProFTPD 1.3.3d on OpenSUSE 64bit Linux 2.6.34.8-0.2-desktop
Java 1.5

• Assignee: Unassigned
• Reporter: Michael Voigt
• Created: 18/May/11 05:28
• Updated: 30/Jun/24 11:31

Description

I have a problem with the FTPClient connecting to a ProFTPD server.

If the server uses the configuration option "TLSProtocol TLSv1", I
cannot connect to it at all. I recieve the following error message:

• javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection

On the server side I see in the log:
unable to accept TLS connection: protocol error:

• (1) error:14094416:SSL routines:SSL3_READ_BYTES:sslv3 alert
  certificate unknown
• TLS/TLS-C negotiation failed on control channel

If the server uses the configuration option "TLSProtocol SSLv23", I
can connect to it but I cant transfer any files. In the server log I
see:

• starting TLS negotiation on data connection
• TLSv1/SSLv3 renegotiation accepted, using cipher RC4-MD5 (128 bits)
• client did not reuse SSL session, rejecting data connection (see
  TLSOption NoSessionReuseRequired)
• unable to open data connection: TLS negotiation failed

If I add the NoSessionReuseRequired parameter to the ProFTPD config
everything works fine.

Here is my code:
FTPClient ftpClient = new FTPClient();
ftpClient = new FTPSClient("TLS");

// this throws an exception with TLSProtocol TLSv1
ftpClient.connect(host, port);

int reply = ftpClient.getReplyCode();
if (!FTPReply.isPositiveCompletion(reply))

{ ftpClient.disconnect(); log.error("The FTP Server did not return a positive completion reply!"); throw new FtpTransferException(ECCUtils.ERROR_FTP_CONNECTION); }

boolean loginSuccessful = ftpClient.login(userName, password);
if (!loginSuccessful)

{ log.error("Login to the FTP Server failed! The credentials are not valid."); throw new FtpTransferException(ECCUtils.ERROR_FTP_LOGIN); }

ftpClient.execPBSZ(0);
ftpClient.execPROT("P");

boolean success = ftpClient.storeFile(fileName, fis);
if (!success)

{ // this is false if "NoSessionReuseRequired" is not set }

Now my question is if it is generally possible to connect to a server
with "TLSProtocol TLSv1" or "TLSProtocol SSLv23" without the
"NoSessionReuseRequired" parameter? Could someone provide a piece of
example code for this?

Issue Links

• is duplicated by: NET-723 FTPSClient cannot transfer files to FileZilla Server 1.7.2
• is related to: NET-426 FTPS: Hook to customize _openDataConnection_ SSLSocket before startHandshake() is called