Mastering Linux Security and Hardening

Hands-on lab for nftables on Ubuntu

For this lab, you need a clean snapshot of your Ubuntu virtual machine:

1. Restore your Ubuntu virtual machine to a clean snapshot to clear out any firewall configurations that you created previously. Verify with the commands:

        sudo ufw status        sudo iptables -L

You should see no rules listed for iptables, and the ufw status should be inactive.

2. Install the nftables package:

        sudo apt install nftables

3. List the tables, which should give you no output. Load the default configuration file, and list both the tables and the rules:

        sudo nft list tables        sudo nft -f /etc/nftables.conf        sudo nft list tables        sudo nft list table inet filter

4. Make a backup copy of the nftables configuration file:

 sudo cp /etc/nftables.conf ...