Debugging with tcpdump
I’m having some problems with one of my hobby servers but this time instead of looking at the code to try to figure out what is happening, I decided to try to do it using only tcpdump. I was trying to start my server and I got this error message:
1
failed to create GA auth provider: invalid character '\u003c' looking for beginning of value
The character ‘\u003c’ translates to <, so it seemed like the problem was that somewhere in my GA auth library I was getting what looked like an HTML instead of a JSON. The first thing I did was monitor the HTTP traffic using this command:
1
tcpdump -c 20 -s 0 -i eth0 -A tcp port http