How does a ftp-server log real ip-address of client machine?

[Robert Ransom]

On Wed, 29 Dec 2010 21:12:36 +0000
Orionjur Tor-admin <tor-admin at orionjurinform.com> wrote:

> I usually connect to my servers through the Tor.
> When I connecting with them through ssh or sffp I don't find any serious
> in logs of my server except ip--addresses or names of apropriate
> exit-nodes of the Tor.
> But when I connect with them through ftp immediate (without ssh) I can
> see real ip-addresses of my client's machine such the next:
> proftpd[32816] someuser (anonymizer2.torservers.net[174.36.199.200]):
> Refused PORT 192,168,1,5,203,191 (address mismatch)
> As I understand if my machine would not be behind NAT and have 'white'
> ip-address my anonimity would be compromised.
> How does a ftp-server log real ip-address of client machine? And how I
> can avoid it?

Your FTP client sent your IP address to the server.

To prevent your FTP client from sending your IP address to the server,
you need to use an FTP client that supports 'passive mode', at the very
least.  Setting 'passive mode' may or may not be enough; if you want to
make sure the FTP client you want to use won't leak information, audit
its source code.


Robert Ransom
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