FTP server and port 20 , 21 Firewall Exception

11th April 2006, 14:19

I have configured FTP Server on XP Pro SP2.

I have excepted port 21 , then I was able remotly to FTP to windows XP (FTP Server).

My question, since with FTP, port 21 for control information (commands and response, like ls, put, get,etc) and posrt 20 for data connection.

Shouldn't I have enabled port 20 as well ?

Since I have not enabled, why I was able to do FTP to server

11th April 2006, 14:21

While I was reading I found this link:
http://www.siliconvalleyccie.com/lin...ftp-server.htm

Control Channel (command and response), TCP Port 21 and Data Channel, TCP Port 20

I just wondring if there is a typo in the link above , because he is saying :

Quote:

but any data sent back (such as "ls" directory lists or actual file data in either direction) will go over the data connection.

Quote:

Your client connects to the FTP server by establishing an FTP control connection to port 21 of the server. Your commands such as 'ls' and 'get' are sent over this connection.

I feel there is contradiction between the two quoted above , because "ls" is command which should be sent over Control Channel not Data Channel,,,Am I right ?

jmke · 11th April 2006, 14:24

what he is saying is that the LS data (the file listing) is sent over the data connection; your input command (like ls and get) are sent over port 21.

11th April 2006, 15:36

Quote:

LS data (the file listing) is sent over the data connection; your input command (like ls and get) are sent over port 21.

What is the difference between LS data and ls ?

jmke · 11th April 2006, 15:41

ls command client ---> server: port 21

ls data: the directory listing

server ---> client : port 20

11th April 2006, 14:19	#1
zillah Posts: n/a	FTP server and port 20 , 21 Firewall Exception I have configured FTP Server on XP Pro SP2. I have excepted port 21 , then I was able remotly to FTP to windows XP (FTP Server). My question, since with FTP, port 21 for control information (commands and response, like ls, put, get,etc) and posrt 20 for data connection. Shouldn't I have enabled port 20 as well ? Since I have not enabled, why I was able to do FTP to server

11th April 2006, 14:24	#3
jmke Madshrimp Join Date: May 2002 Location: 7090/Belgium Posts: 79,021	what he is saying is that the LS data (the file listing) is sent over the data connection; your input command (like ls and get) are sent over port 21. __________________

11th April 2006, 15:41	#5
jmke Madshrimp Join Date: May 2002 Location: 7090/Belgium Posts: 79,021	ls command client ---> server: port 21 ls data: the directory listing server ---> client : port 20 __________________

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