> No, dear friend!
> That's exactly what you should understand: The NAT server does this
> translation from private inside addresses and ports to that public
> address and also the reverse!!
>
> The NAT router.
> Try it yourself!
> I assume *your* NAT router has similar capabilities.

I don't know that they all do, you know. I have a LinkSys EtherFast
BEFSR41 and as far as I know, it doesn't alter any packets at all. It's
certainly a feature of some, but not all. We had a NAT router at work
that wasn't doing packet twiddling, either, I think I recall, and that
caused a lot of problems for FTP.

What does seem to work, though, is that if the server sees a private IP
for a data port, discards it and uses the same address as the control
connection.

I'd certainly be interested to try it -- see what someone else's FTP
server gets at their end when I try to connect actively. Typically,
though, I think I've had a variety of problems with port mode (which if
addresses are being altered, I should not) that passive mode solved.
Received on 2007-02-12