christophvoigt.com

A Netcat HTTP Server

Christoph Voigt -

Netcat is a versatile tool - I learned about it way too late in my career. It can be used as a TCP-server or client. As HTTP is based on TCP, Netcat can even be used to have some fun with HTTP:

This is how to tell nc to listen to new connections on port 8080:

$ nc -l 8080

Pointing your Browser or another HTTP client like curl on localhost:8080:

$ curl localhost:8080/index.html

Netcat will show you the incoming HTTP request immediately:

$ nc -l 8080
GET /index.html HTTP/1.1
Host: localhost:8080
User-Agent: curl/7.64.1
Accept: */*

Lets create an actual file index.html and serve it via Netcat:

# Create the file
$ cat << EOF > index.html
<!doctype html>
<html>
  <body>
    <h1>Hello from Netcat!</h1>
  </body>
</html>
EOF

# Serve index.html
$ while true; do
  cat index.html | nc -l 8080
done

Directing the Browser to localhost:8080:

We can even use nc to perform the HTTP request:

$ echo "GET / HTTP/1.0\r\nHost: localhost\r\n\r\n" | nc localhost 8080
HTTP/1.1 200 OK
Content-Type: text/html; charset=UTF-8
Server: netcat!

<!doctype html>
<html>
  <body>
    <h1>Hello from Netcat!</h1>
  </body>
</html>