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Chapter 4. FTP

The File Transfer Protocol (FTP) is a standard network protocol used for the transfer of computer files between a client and server on a computer network. dCache supports varous extensions allow you to list files with FTP and manage them.


The GridFTP protocol extensions support a number of advanced features. On of these features is to protect the control channel and allow the client to negotiate a secure data channel, as described in RFC 2228.

dCache supports GridFTP with a secure control channel, but does not support a secure data channel: all data is transferred unencrypted.


The globus-url-copy command supports the options -dcpriv (or, equivalently, -data-channel-private) that the man page describe as:

Set data channel protection mode to PRIVATE

There is a bug where a transfer with the -dcpriv (or -data-channel-private) option specified will succeed with dCache, but the file’s contents is sent unencrypted over the network.

Therefore we recommend that you NEVER use the -dcpriv or the -data-channel-private option as it’s behaviour is unreliable.

For more details, see the original report GT issue #121, and the status under GTC GCT issue #62.