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

Stop curl from lying to you about silent connection failures

🧩 The Challenge

Everyone has spent an hour chasing a ghost in the firewall, convinced their packet is getting through, when actually curl is just failing silently because of a misconfigured proxy or a hidden header mismatch. It’s infuriating when you think the server is down, but the client is just playing games with you.

💡 The Fix

Use the verbose and trace flags to force curl to dump every single handshake and header exchange to your terminal. It turns a black box into a clear roadmap of exactly where the conversation dies.

curl -v --trace-ascii /dev/stdout http://your-problematic-endpoint.com

⚙️ Why It Works

Adding the trace-ascii flag forces a hex dump of all incoming and outgoing data, which bypasses the standard “curl just died” ambiguity and shows you if you are hitting a WAF or getting rejected by a load balancer mid-request.

🚀 Pro-Tip: Pipe it to less if you are debugging a massive JSON response so your terminal doesn’t turn into a scrolling nightmare.

Linux Tips & Tricks | © ngelinux.com | 7/28/2026