Re: iSeries SSL FTP to WS-FTP server??

Hi Steve,

Problem 2 (another client) -

[SNIP]

Unknown protocol appears to indicate that this site is not using SSL
but they insist that they are. The connection port is 21 - could
they be doing something behind their firewall that would cause this
result? (NAT, maybe?)

No, it couldn't be NAT. NAT-related problems in FTP usually occur when you try to do a file transfer or directory listing. (And it doesn't sound like you're getting that far, yet.)

More likely, they're running both SSL and non-SSL on the same port. You see, there's two ways to use SSL in FTP. There's "implicit" mode, in that situation an SSL connection is established immediately when you connect -- that's what you had in your first case. Implicit mode is usually run on port 990.

Then there's explicit mode, where FTP connects and sends a command (unencrypted) to the server to tell it to upgrade the connection to SSL. Since OpenSSL is not an FTP client, it doesn't know that it has to send commands to start FTP in explicit mode, and therefore doesn't know how to tell the server to upgrade the connection...