Re: Forwarding FTP with PuTTY

From: Richard E Silverman (res_at_qoxp.net)
Date: 06/07/03 

Date: 06 Jun 2003 22:48:09 -0400

>>>>> "Hactar" == Hactar <ebenONE@tampabay.ARE-ARE.com.unmunge> writes:

    Hactar> In article <bbqlfj$698$1@gladiola.noc.ucla.edu>, Lapp
    Hactar> <lapp@yandex.ru> wrote:
>> I have a server, running SSH (Linux RedHat 8.0) , and I want it to
>> be kind of a gate to access all inner LAN computers from outside
>> (all the TCP ports under 1024 are closed from outside on the router
>> - but SSH to that Linux box). I suppose to use Port Forwarding
>> technique with PuTTY. There is no problem to forward Telnet, but
>> forwarding FTP is an issue. I can easily forward Port 21 for
>> control connection, and I've read, that this is pretty much enough
>> if I don't need to secure the Data flow. But in my case it could
>> not to create a Data connection at all :-( .

    Hactar> Use passive mode FTP. Data and control both go over port 21,
    Hactar> IIRC.

This is wrong -- the TCP connections for data are always separate from
control in FTP, regardless of the "mode." Passive mode simply means that
they will be made from the client to the server, rather than the other way
around.

FTP is simply not amenable to static SSH port forwarding; it is very
awkward and often will not work at all, even if you don't care about
securing the data streams -- recall that the FTP protocol carries explicit
IP addresses and TCP sockets, which are liable to be screwed up by the
forwarding mechanics and the nearly ubiquitous plague of NAT. 

-- 
  Richard Silverman
  res@qoxp.net

Relevant Pages

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