How to close port 21?

Question

linux

I use sftp but the pentest shows that port 21 is open. What is the best way to close, through iptables or by stopping the ftp service? In the case of a reboot, will it rise again and be opened? What's the best way to do it?

Answer 1

SFTP and FTP are two different protocols. The first works via ssh on port 22, and the second on port 21. If no one needs port 21, then it should be closed or even deleted the ftp server

Answer 2

If you do not need ftp, of course, it is best to remove or at least disable it.

Answer 3

Can it be like this

Answer 4

Add an appropriate rule to the IPTables firewall.
iptables -A INPUT -p tcp --dport 21 -j DROP