ftp port forwarding question

[edijs]

Hi!

Recently I examined a router setup. It has a ftp server behind it. When I looked into the forwarded prots section, I saw that besides other forwards, there were forwards as follows:

FTP      /port range/
FTP_PASSIVE  /port range/

Am I correct in thinking that FTP is for active connections and passive for passive? Meaning that if I say, delete FTP, people would be able to connect only by using active FTP? I'm a bit confused here.

 

[thoonie]

Read here between the difference of Active and Passive FTP connection.

 

[edijs]

okay, so basically FTP should always be 21 for the commands and FTP_PASSIVE should define a limited port range which I am willing, as a FTP server admin, to supply for a wide range of users (since a number will be using passive FTP). Is that about it?

and one more thing:

is it just custom or is there something behind the fact that like FTP command port is 21, ssh usually is 22, remote admins use 8080, http uses 80...

 

[Addis]

Those are the default ports for those TCP services, but they don't necessarily have to be. For security, sometimes ssh is moved from port 22 to another one. When you use something like ftp://server.domain.com ftp:// implies that the port is 21, but if you want to access it via a different port then you would do ftp://server.domain.com:portnumber