Reading response headers

The server introduces itself

Before attacking anything, work out what you're attacking. Servers volunteer a surprising amount in their response headers. Ask for only the headers with -I (a HEAD request):

curl -sI http://127.0.0.1:8080/

In the terminal

student@vulntech:~$ curl -sI http://127.0.0.1:8080/
HTTP/1.1 200 OK
Server: Werkzeug/2.2.2 Python/3.11.2
Date: Sun, 18 Oct 2026 12:30:06 GMT
Content-Type: text/html; charset=utf-8
Content-Length: 700
Connection: close

The Server: header names the web server — here a Python stack. Content-Type: tells you what the body is. Knowing the server and language narrows the vulnerabilities worth trying and the payloads that will work.

Tip: Headers can be removed or faked, so never trust them — but when they're present, they're a free head start.