Firewall-CMD

firewall-cmd --zone=public --permanent --add-port 389/tcp
firewall-cmd --reload

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UFW

Installation in Ubuntu/Kali/Debian

apt update
apt install ufw

Checking status

ufw status

Reloading firewall

ufw reload

Enabling/Disabling UFW

ufw enable
ufw disable

Allowing incoming local port access

ufw allow <PORT_NUMBER>

Denying incoming local port access

ufw deny <PORT_NUMBER>

Block incoming traffic from a specific IP address

ufw deny from <IP_ADDRESS>

Block outgoing traffic to a specific IP address

ufw deny out from <IP_ADDRESS>