vsftpd, which stands for Very Secure FTP Daemon, is an FTP server under Ubuntu, Fedora Core, Red Hat Enterprise Linux and a number of other distributions. Changing a default port is a good idea. FTP is a common method for allowing remote access to files. Like telnet, the FTP protocol is unencrypted, which means that passwords and other data transmitted during the session can be captured and that the session is vulnerable to hijacking.
Changing vsftp port
All you need to do is edit the configuration file for vsftpd server. The default configuration file is /etc/vsftp/vsftpd.conf or /etc/vsftpd.conf.
First login as root user.
Open the vsftpd.conf file, enter:
# vi vsftpd.conf
Find line that read as follows
Replace port 21 with new port such as 201:
Save and close the file. Please make sure no other service is using port # 201. Finally, restart the vsftpd server:
# /etc/init.d/vsftpd restart
# service vsftpd restart
All ftp client need use the tcp port # 201 while connecting to the ftp server. For example:
$ ftp ftp.cyberciti.biz 201