How to Setup and Config UFW on VPS

What is Firewall ?

A firewall is computer hardware or software that controls inbound and outbound traffic of a machine.

What is UFW ?

UFW (Uncomplicated Firewall) is presented as a front-end of Iptables. By default, UFW denies all incoming connections and allows all outgoing connections.

• To Get Access via SSH

Syntax:- ssh -p PORT USERNAME@HOSTIP
Example:- ssh -p 22 [email protected]

• Install UFW

apt install ufw

• Enable UFW

ufw enable

• Check UFW Status

To Check Normal Mode: ufw status 
To Check in more Comprehensive: ufw status verbose
To Check with Number: ufw status numbered

• Configure to support IPv6:

Open Config File: nano /etc/default/ufw
then Change: IPV6=yes

• To Restart Firewall Disable it then Enable it:

ufw disable
ufw enable

• To Check Open Port, It will show only those which are currently running:

netstat -tulpn

• To Open Port:

Syntax:- ufw allow port/protocol
Example:- ufw allow 21/tcp

• To Close Port:

Syntax:- ufw deny port/protocol
Example:- ufw deny 21/tcp

• To Open a Range of Ports:

Syntax:- ufw allow [Starting_port:Ending_port]/protocol
Example:- ufw allow 300:310/tcp

• To Close a Range of Ports:

Syntax:- ufw deny [Starting_port:Ending_port]/protocol
Example:- ufw deny 300:310/tcp

• To Allow Service:

Syntax:- ufw allow service_name
Example:- ufw allow http

• To Deny Service:

Syntax:- ufw deny service_name
Example:- ufw deny http

• To Allow Access to IP Address:

Syntax:- ufw allow from IPAddress
Example:- ufw allow from 192.168.1.4

• To Deny Access for IP Address:

Syntax:- ufw deny from IPAddress
Example:- ufw deny from 192.168.1.5

• To Allow IP to connect only specific Port:

Syntax:- ufw allow from IPAdress to any port Port
Example:- ufw allow from 192.168.1.4 to any port 45

• To Delete a Specific Rule:

1. Check Status with Number: ufw status numbered
2. Delete with Number 
   Syntax:- ufw delete number
   Example:- ufw delete 3

• To Reset to Default Setting:

ufw reset

• Some usefull connection which You may want to allow

To Allow SSH Connection: ufw allow ssh or ufw allow 22/tcp
To Secure Web Server: ufw allow 80/tcp
To Allow FTP Connection: ufw allow ftp or ufw allow 21/tcp and 20/ftp
To Allow Web Server Profile: ufw allow www