[ih] Why FTP uses two ports?

[Dave Crocker]

On 6/20/2012 9:33 PM, Louis A. Mamakos wrote:
>> I want to know if anyone remembers the origins of FTP and the reason why FTP uses two ports.
>
> You can perform 3rd party file transfers, with one client orchestrating the transfer between two
> different servers.


It also allows "pure" binary exchanges.  Doing the transfer inline with 
the command channel requires an escape mechanism to get back to command 
mode.

This was back in the days when character-level processing, for this, was 
deemed expensive.

d/

-- 
  Dave Crocker
  Brandenburg InternetWorking
  bbiw.net