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

Debug network connections when curl is giving you zero clues

🧩 The Challenge

Dealing with a connection that just hangs forever is enough to make anyone scream. You check the server, check the firewall, and curl just sits there blinking until it eventually times out.

💡 The Fix

Use the trace-ascii flag in curl to see every single byte moving across the wire. It exposes those silent handshake failures that standard error messages ignore.

curl -v --trace-ascii - http://target-host.example.com

⚙️ Why It Works

Dumping the hex and text output directly to your terminal forces you to see exactly where the negotiation breaks down, like a failed SSL handshake or a hanging proxy. Seeing the full conversation is often the only way to prove the packet isn’t actually reaching the application layer.

🚀 Pro-Tip: Pipe it into less or grep for ‘SSL’ to save your sanity when the handshake dump is a hundred lines long.

Linux Tips & Tricks | © ngelinux.com | 9/13/2026