Usually, if you change the port in a server's configuration file, you will have to stop and restart its daemon or service for the changes to take effect. Changing the FTP port would not stop access, butyou would probably have to specify the port manually on any FTP client.
The network protocol that uses port 21 is FTP (File Transfer Protocol). FTP is commonly used for transferring files between a client and a server on a computer network. Port 21 is specifically designated for FTP control connections. When a user initiates an FTP connection, the client connects to the server's port 21 to establish communication for sending and receiving files. It is important to note that FTP operates in two modes: active mode and passive mode, each using different ports for data transfer.
Ftp
If I understand the question aright; different port numbers are used to identify different protocols. Port numbers between 1 and 1023 are well-known numbers and standards define which protocol uses which. FTP uses port number 21, HTTP uses port 80.
Cute FTP is a FTP client (used to connect to a server). FTP is a point-to-point protocol used for file transfert (FTP meaning File Transfert Protocol).
FTP is File Transfer Protocol. It is the protocol used on the internet when you upload files or download files. So for example, if you create a webpage and you want to upload it to your webspace, you need to use an FTP program. There are lots of good one out there. If you use Firefox, you can get an add-on called FireFTP. You would need to get the details of where to connect to in order to get access to your webspace. You will get those on your internet providers webspace. You then set the appropriate settings in the FTP program to enable the connection to be made.
The FTP port has been standardized at port 21, so it is highly unlikely it is operating on another port. To change the port, you would have had to change configuration settings. And if you had, you would know what port it was on.
Generally port 21 is for FTP 22 for FTP using SSH 990 FTP using SSL
The default FTP port is 21. But most FTP server software allows you to set which ever port you want.
port 21
Students and professors will be unable to Telnet to the server or FTP files to or from the server
Implicit FTPS runs on port 990 by default.
21
Only in Montenegro (ME)
port 21
This actually doesn't make a whole lot of sense. If your trying to listen in on an FTP port, then it's 21. If you are running an FTP server, then the option is in your software. If you are just trying to connect to an FTP server on a non-standard port than using a colon and the port after the host will work fine. If your question is referring to allowing another port into the built-in firewall, then just add a port and call it what you want. If you could provide me with more information I might be able to help you further.
TCP port 20 is used by FTP (File Transfer Protocol) for data transfer. FTP also uses port 21.
External FTP ports are generated. They are not sold unless you are paying someone to do it for you. To help you create an FTP port simply open port21 on your router.