Re: ftp?

["Marc-Adrian Napoli" <marcadrian@cia.com.au>]

hi all,

that makes perfect sense, i'll let the customer know ;-)

thanks to all!

Regards,

Marc-Adrian Napoli
Network Admin
Connect Infobahn Australia
+61 2 9212 0387


> Marc-Adrian Napoli wrote:
> >
> > hi,
> >
> > have a wierd problem here. we have standard debian box here running
wuftp,
> > as well as an NT box with iis 5.0. (and ftp)
> >
> > a particular customer sitting behind a NAT'd firewall cant connect to
our
> > debian wuftp server, but has no problem with the NT box.
> >
> > ive allowed their specific class C range access in hosts.allow and i can
ftp
> > into the box with their account no problems.
> >
> > the customer gets an FTP connection but no prompt for username and
password,
> > has anyone seen this before?
> >
>
>    This is a fairly common problem with trying to run FTP through a
> firewall. FTP creates two connections: an outbound connection and a
> return connection.
>
>   The outbound conection is easy: from the clients unprivledged ports to
> the server port 21 and back.
>  The return connection is a problem. You have to allow *anyone* to
> connect to your port 20.
>
>   The reason that you do not get a login prompt is that the firewall is
> rejecting the inbound connection.
>
>  Often you can get around this problem by using passive mode FTP (which
> is probably why they can connect to the M$ box) which connects to one of
> your unprivledged ports instead of 20.
>
> Another way around the problem if your client doesn't want to mess with
> their firewall is to offer HTTP based FTP.
>
> Pete
>