iptables

command firewall

Configure packet filtering rules (netfilter)

Required Packages

sudo apt install -y iptables

Options

Table (-t)

Select the table (default: filter)

Action *

Chain

Empty for all chains (useful with -L/-F)

Protocol (-p)

Source port (--sport)

e.g. 1024:65535, 80

Destination port (--dport)

e.g. 22, 80, 443, 8080:8090

Source address (-s)

e.g. 192.168.1.0/24, 10.0.0.1

Destination address (-d)

Input interface (-i)

e.g. eth0, ens33 (for INPUT/FORWARD/PREROUTING)

Output interface (-o)

e.g. eth0, ens33 (for OUTPUT/FORWARD/POSTROUTING)

Connection state (-m conntrack --ctstate)

e.g. NEW, ESTABLISHED, RELATED (comma-separated)

Target (-j)

sudo iptables -A -j ACCEPT