[web] How to send an HTTP request using Telnet

For posterity, your question was how to send an http request to https://stackoverflow.com/questions. The real answer is: you cannot with telnet, cause this is an https-only reachable url.

So, you might want to use openssl instead of telnet, like this for instance

$ openssl s_client -connect stackoverflow.com:443
...
---
GET /questions HTTP/1.1
Host: stackoverflow.com

This will give you the https response.