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

Stop chasing ghosts when curl fails

🧩 The Challenge

Everyone has dealt with a curl request that just sits there hanging until it eventually times out, leaving you staring at the terminal wondering if the server is dead or the firewall is silently nuking your packets. I’ve wasted whole afternoons debugging routing tables only to find out it was a simple path MTU issue.

💡 The Fix

Use the verbose flag alongside the –trace-ascii option to dump the entire handshake process to a file so you can see exactly which stage the connection hits a wall. It cuts through the guesswork by showing you the raw traffic flow.

curl -v --trace-ascii dump.txt https://your-site-here.com

⚙️ Why It Works

This works because it captures the interaction between your client and the remote host, including the hex dump of data buffers, which tells you immediately if you’re getting a TCP handshake but failing at the TLS negotiation phase. That distinction saves you from chasing network issues when it’s actually a certificate or proxy problem.

🚀 Pro-Tip: Toss –retry 3 into your command when testing flaky connections so you don’t have to mash the up-arrow key every time the handshake stumbles.

Linux Tips & Tricks | © ngelinux.com | 9/17/2026