The last two numbers give the port information to the client so the
client can connect back to the server for sending/receiving data. The
actual port number is calculated using (256*n1) + n2. Of course, this
is the standard syntax defined in the FTP protocol.

Regards,
Sai Pullabhotla





On Fri, Mar 12, 2010 at 8:21 AM, Aidan Diffey
<[email protected]> wrote:
> Just out of interest, what do the numbers mean in the line:
>
> *227 Entering Passive Mode (10,101,64,144,173,138)*
>
> I can see the 10 101 64 144 is the IP address of the server, but what about
> the 173, 138 numbers?
>
> On Fri, Mar 12, 2010 at 2:07 PM, Aidan Diffey
> <[email protected]>wrote:
>
>> Sorry, that IP tables entry should have been:
>>
>>
>> *DNAT       tcp  --  anywhere             anywhere            tcp dpt:ftp
>> to:10.101.64.144:10121
>> *
>>
>>
>>
>> On Fri, Mar 12, 2010 at 1:56 PM, Niklas Gustavsson 
>> <[email protected]>wrote:
>>
>>> On Fri, Mar 12, 2010 at 2:46 PM, Niklas Gustavsson <[email protected]>
>>> wrote:
>>> > In these case, are you really running behind iptables? Because, it
>>> > struck me that since you map the ports, the client will try to connect
>>> > to the server on 10120 since that's what the server told him to do in
>>> > the response to the PASV command. He will not know to connect on port
>>> > 20.
>>>
>>> That being said, we currently support providing an "external" IP
>>> address for passive connection, for use when we're behind a NAT. But,
>>> we do not support providing an "external" port, for this kind of use.
>>> We surely could, if people are really interested in port mapping
>>> passive connections. I doubt it is that useful, but who knows :-)
>>>
>>> /niklas
>>>
>>
>>
>

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