A firewall allows or denys access to a particular networking port on server.

I want my specific IP address to be able to access to SSH on the sever and nobody else. So, even within a network, only my admin IP can SSH to the server.

uncomplicate firewar

1. General

status:

sudo ufw status verbose

enable

sudo ufw enable

Deny all incoming connection by default

Add rule

sudo ufw allow 21

sudo ufw status verbose

Allow a ip to access a port sudo ufw allow from 192.168.1.4 to any port 22 sudo ufw status verbose

Allow for a whole subnetwork access to aport sudo ufw allow from 10.0.1.0/24 to any port 22

Allow a service sudo ufw allow ftp

Remove rule

sudo ufw status numbered

sudo ufw delete 2

Delete all the rule and disable ufw sudo ufw reset