Re: odd behavior

On Mon, Mar 25, 2002 at 03:48:19PM -0500, Paul Jarc wrote:
> Oezguer Kesim <[email protected]> wrote:
> > Get a book on FTP and learn the definition of ACTIVE and PASSIVE modes of
> > data transfer within FTP.
> 
> <URL:http://cr.yp.to/ftp/retr.html#port>
> <URL:http://cr.yp.to/ftp/retr.html#pasv>
> <URL:http://cr.yp.to/ftp/security.html>
 
Right, ok.  So I investigated my firewall/router and discovered that
it snoops on PASV requests and automatically sets up the new incoming
tcp connection to forward to the publicfile server IP.

I wondered why this isn't working for me, but then checked various
ftp clients.  Sure enough:

ftp://triceratops.com/

works for clients which force PASV mode (at least, I believe this is
what's happening), such as ncftpd and lynx.  In fact, I just tried the
-p (force passive) flag on my command line ftp client (RedHat 6.2, only
hint of the origin is 'Linux NetKit 0.16 at the bottom), or using 'pftp'.

My firewall is handling PASV mode data transfer correctly.

So, my question is, what kind of tcp connections are being made if the
client doesn't send PASV?  I assume that's what's happening with my
stock ftp command line.

--
John White