Subject: Re: ipnat ftp proxy: any news?
To: None <email@example.com>
From: Matthias Scheler <firstname.lastname@example.org>
Date: 09/05/2004 12:58:03
On Sun, Sep 05, 2004 at 12:52:00PM +0200, Pelle Johansson wrote:
> Up until the point the client sends the EPSV ALL command. When that's
> done it can let go of the connection, since it knows the client will
> only use passive transfers.
That's not correct:
1.) Even if the client sends a "EPSV ALL" command the FTP proxy doesn't
know yet whether the FTP server will accept that command.
2.) Even if the FTP server supports passive connections the FTP client
might later decide to use active connections(*).
(*) I encountered a FTP server behind a broken firewall yesterday. Because
the firewall blocked incoming connection to most ports including ports
above 1023 NetBSD's FTP client had to fallback to active connections
to download files although the FTP server supported active connections.
Matthias Scheler http://scheler.de/~matthias/