FTP oddness, over SSH session.

[Dave B]

On 12 Apr 2012 at 12:40, Da Rock wrote:

> On 04/11/12 21:51, Dave B wrote:
> > FreeBSD FBSD.67MK181QZ 8.0-RELEASE FreeBSD 8.0-RELEASE #0:
> > Wed Apr 14 22:55:09 BST 2010
> > root at FBSD.67MK181QZ:/usr/obj/usr/src/sys/PPSGENERIC  i386
> >
> > Hi.
> >
> > I have a small FreeBSD 8.0 system (above, yes I know, not current,
> > but it works.) That is mainly used for timekeeping with an attached
> > PPS equipped GPS.  No problems with that.
> >
> > It also has a small web server (Hiawatha) FTP server and SSH portal,
> > for my own use.
> >
> > The FTP "server" is the built-in OS based ftpd implementation, and
> > works well for all that I need.
> >
> > Anyway...  I found a while ago, that I can tunnel connections into
> > my home LAN via a SSH session to my FreeBSD box, from outside the
> > LAN using PuTTY (on Windows XP) from wherever I am.  It's been a
> > useful dodge for me to do that so as to VNC to other boxes that are
> > there.   The needed SSH working port, is not the usual suspect, it's
> > way up high, well away from script kiddies etc.
> >
> > I just found however, that though I can reliably send a file to the
> > FTP server and it get's saved just fine, that's not true when
> > connecting this way using a SSH tunnel.
> >
> > Over the SSH session, (using Passive Mode, with all needed ports
> > forwarded, plus the FTP daemon's data port usage restricted to the
> > same range as those tunneled.)  Though the FTP process appears to
> > work OK, with no errors, the file sent to and deposited on the
> > server ends up as name only, and zero bytes in length.
> >
> > Oddly, I can successfully create a new folder on the FTP server over
> > the SSH session using the FTP client, and that works just fine.
> >
> > The FTP client I'm using, is the same FileZilla both times.
> > (V3.1.0.1  I may go look for any updates, just in case.)
> >
> > Downloading works fine regardless of how I connect, it's just
> > uploading that's screwey.  I suspect (as usual) it's a rights issue,
> > but even if I su - root after the initial SSH login, it changes
> > nothing.
> 
> I'd check the ports you are forwarding over ssh. Two ports are
> required for ftp and it sounds like one is blocking for some reason-
> the control channel seems to be working fine though :) 

As I suspect too, but as yet, I've not figured it out.  I can as above 
download files just fine, so the data channel can be established for 
that, and I am using Passive Mode, so it *Should* be only my end (the 
client) that initiates a connection for the data channel.

Also, two versions of FileZilla *Appear* to succeed uploading a file, no 
errors regarding being unable to setup a data channel, just that when you 
look on the FreeBSD box later, the file is zero bytes in size.

Regards.

Dave Baxter.