sudo tcpdump -i lo -A port 3000

Category: Web App Development

sudo tcpdump -i lo -A port 3000

Capture raw HTTP traffic on the loopback interface

Prints every packet on the loopback interface for port 3000, with -A showing the payload as ASCII so HTTP headers are readable. Loopback traffic often escapes normal sniffing tools, making this the way to see exact bytes. Needs root for packet capture.
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