Ping Pong!

A quick peek at networking

You'll use these constantly the second you run Linux for real, so they're worth knowing.

ping

ping checks if another computer (or website) is reachable by firing tiny messages at it and waiting for a reply.

[user@linux]$ ping google.com

It keeps going forever until you hit Ctrl+C. Each reply shows how long it took in milliseconds. Nothing coming back means the other side is down or something is blocking you.

💡 Want it to stop on its own? ping -c 4 google.com sends 4 and quits.

curl

curl grabs whatever is at a web address and prints it straight into your terminal.

[user@linux]$ curl example.com

What you get back is the raw HTML of the page, the same stuff your browser reads to draw it. That includes stuff your browser doesn't show you, like comments developers left in the code. In cybersecurity, curl gets used all the time to poke at websites without ever opening a browser.

💡 Your practice box isn't connected to the internet, so curl example.com won't work in there. Don't worry, you'll get a website of your own to curl in a minute.

localhost

localhost is a special name that always means "this computer, right here." It's how a computer talks to itself.

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Try it

The CyberAcad Ping Pong Club has a tiny website running right inside your box, at http://localhost:8080. Alex built it. Alex also left something in it that was never supposed to be public.

We'll go way deeper into networking in a future course. (Wink wink.)