ftp confusion/want active connections
I am confused on how FTP uses both port 20 and 21. Which ports should go through the firewalls and routers? Also, when connecting to remote ftp machines on some networks (with firewalls) I can go default which an active connection. Here, at least on the unix machines, I must make a passive connetion as soon as I login. So what is diff in active and passive and how can I get active connections behind blocked ports?