Why Your Port Forwarding Isn’t Working A very common mistake with port forwarding on Linux is assuming a single DNAT rule is enough. You add one iptables rule, try to hit your server from outside, and… nothing. In reality, proper forwarding through a Linux gateway needs three things working together: IP forwarding in the kernel, packet filtering rules in the…
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If you’re staring at a wall of iptables rules wondering what on earth is going on, you’re not alone. Linux firewalls can feel hostile when all you want is: “Let the right packets in, keep the wrong packets out, and don’t break SSH.” This guide walks through the basic architecture of iptables and netfilter so you understand where your rules…
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Before and After: Fighting the Firewall Beast Before: you SSH into your Ubuntu server, start reading about iptables, get hit with words like chains and policies, and five minutes later you’re staring at a command that might lock you out of your own box. After: you use ufw with a few simple commands, knowing it’s just talking to iptables for…
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