ufw - program for managing a netfilter firewall

To check ufw status
$ sudo ufw status

To enable ufw 
$ sudo ufw enable

To disable ufw
$ sudo ufw disable

To show ufw rules, along with their numbers
$ sudo ufw status numbered

To reset ufw to its default state
$ sudo ufw reset

To view firewall reports 
$ sudo ufw show added
$ sudo ufw show raw

To set ufw logging levels 
$ sudo ufw logging on
$ sudo ufw logging high
$ sudo ufw logging medium
$ sudo ufw logging low
$ sudo ufw logging full

To allow service
$ sudo ufw allow openssh

To deny service
$ sudo ufw deny openssh

To view all application profiles
$ sudo ufw app list

To get more information about a particular profile and defined rules
$ sudo ufw app info 'Apache'

To reject outgoing FTP connections
$ sudo ufw reject out ftp

To add a new rule at a specific number
$ sudo ufw insert 1 allow 80/tcp
$ sudo ufw insert 2 allow 443/tcp 

To Delete rules by specifying their numbers
$ sudo ufw status numbered
$ sudo ufw ufw delete 1   (will delete above rule allow 80/tcp)

To Deleting rules by service
$ sudo ufw delete allow ftp
$ sudo ufw delete allow openssh

To allow or deny a specific port for a given IP address
$ sudo ufw allow from 192.168.122.100 to any port 8081
$ sudo ufw deny from 192.168.122.100 to any port 8080

To allow an entire subnet
$ sudo ufw allow from 10.0.1.0/16

To Allow Network Subnets to Specific Port
$ sudo ufw allow from 192.168.1.0/24 to any port 22

To Allow Specific Network Interface
$ sudo ufw allow in on eth1 to any port 22

To open all ports for a particular IP address
$ sudo ufw allow from 192.168.122.100

To allow all ports in a range by specifying a port range
$ sudo ufw allow 20:450/tcp

To get a numbered list of added rules
$ sudo ufw status numbered

To check all added rules before starting the firewall
$ sudo ufw show added

To Allow only TCP traffic over HTTP/80
$ sudo ufw allow http/tcp
$ sudo ufw allow 80/tcp

To deny incoming FTP traffic
$ sudo ufw deny ftp/tcp
$ sudo ufw deny 21/tcp

To add a new rule to allow SSH
$ sudo ufw allow ssh
$ sudo ufw allow 22/tcp

To rate limiting service
$ sudo ufw limit ssh/tcp

To print verbose
$ sudo ufw status verbose

To reload ufw 
$ sudo ufw reload 

To Dry Run UFW Rules
$ sudo ufw --dry-run enable



regards,
T.Dhanasekar