Container Networking Debugging: tcpdump, nsenter, and What Packets Are Actually Doing

Thu, 17 Jul 2025 16:00:00 +0000

Container networking is one of those things that works beautifully right up until it doesn’t, at which point you’re staring at connection refused while three different layers of NAT, bridge interfaces and iptables rules all insist they’re innocent. The frustrating part is that the container is usually a minimal image with no ping, no curl, no tcpdump — nothing you’d use to actually see what’s happening. So you guess, you restart things, and eventually it “fixes itself,” which is the worst possible outcome because now you don’t know what was wrong. Here’s how to stop guessing.

Debugging - Tag - vo.rs

Container Networking Debugging: tcpdump, nsenter, and What Packets Are Actually Doing