Networking & Firewall (Ss/Netstat/Iptables/Nftables/Curl)

Stop iptables from keeping rules that break your next boot

🧩 The Challenge

You finally get your firewall rules perfect after an hour of tweaking, only to reboot the server and find that everything you just did has completely vanished into thin air. It is infuriating to watch your carefully crafted blocklists reset themselves because you forgot to tell the kernel to actually remember them.

💡 The Fix

Use the netfilter-persistent package to save your active rules into a file that gets loaded automatically during the boot sequence. It saves you from having to manually reload a script or deal with a wide-open server after an unexpected power cycle.

iptables-save > /etc/iptables/rules.v4
apt install iptables-persistent
netfilter-persistent save

⚙️ Why It Works

Writing the rules to this specific file ensures that the service triggers on startup, effectively re-applying your memory-resident rules as a static config. By using the standard persistence package, you integrate into the systemd flow instead of hacking together your own crusty init scripts.

🚀 Pro-Tip: Always run a test script that drops your SSH connection if the firewall is misconfigured before you lock down the rules permanently.

Linux Tips & Tricks | © ngelinux.com | 7/23/2026