Security is relative. Will these steps make your server “secure”? Sort of. It will be more secure than it was before. And more secure than most servers. Your server will not be “low hanging fruit”. Security is an on-going process. It includes settings, practices and procedures. Make it your business to regularly read about security and [...]
See also: Securing an Ubuntu Server
UFW community documentation: https://help.ubuntu.com/community/UFW
UFW server documentation: https://help.ubuntu.com/10.04/serverguide/C/firewall.html
UFW page: https://wiki.ubuntu.com/UncomplicatedFirewall
Implementing a basic firewall on your Ubuntu server is simple.
UFW (Uncomplicated Firewall) is a simple configurator for Netfilter, the packet filtering system that is built into the Linux kernel. This will then filter IP packets that arrive at the server by port number. [...]
UPDATE: This port is obsolete, see: Passive Mode (PASV) FTP client on an Ubuntu server
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