Requesting Header Through Telnet:
It's actually very simple using Telnet to connect to a webserver and download HTML
or other files.
First you need to connect to the server using an IP address or hostname:
$ telnet XXX.XX.XX.XXX 80
Then request the page you want. HEAD and GET are the most common options.
HEAD will return information about the requested file/page, but not the content.
GET will retrieve both the Header information as well as the content, terminated
with 0. Following the HEAD/GET command you need to specify HTTP/1.1. Then
on the next line specify the Host domain name. HTTP/1.1 allows for multiple
domains to be hosted at a single IP address so this is important. The User-Agent
and other options can be specified on subsequent lines.
GET / HTTP/1.1 Host: www.example.com User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)
The command is executed after a blank line is entered.
Requesting a secure (HTTPS) address:
To request a page from a secure (SSL) server on port 443 you can use openssl instead of telnet. Other than that the method is the same:
$ openssl s_client -connect XXX.XX.XX.XXX:443 ... connection information will be displayed ... GET / HTTP/1.1 Host: www.example.com
This is useful for testing whether a web server certificate has been installed
properly without having to update the DNS before you can check.
To open an SSL connection to a live website you should always connect
using the domain name and not the ip address.