This article describes how to connect to a TCP port 80 on a Web server using telnet.
HTTP Protocol Basics
HTTP is a simple text protocol. So telnet lets you easily test the operation of port 80.
You can test the connection using the following Linux commands:
telnet SERVERNAME 80. Telnet will simply connect to the 80 host port of the specified host name.
- If the connection is established via TCP, telnet will respond with the following response:
Connected to SERVERNAME.and
Escape character is '^]'.
- You can retrieve the site from here by using the HTTP protocol. To do so, enter the following two lines with Enter:
GET / HTTP/1.1
- In the server response we get the HTTP status and the web page (such as HTTP / 1.1 200 OK and so on).
In the following example, we will check the http://richardbuz.de page. With the help of the following Linux commands, enter the commands with enter:
telnet richardbuz.de 80
GET / HTTP/1.1
The richardbuz.de server will reply to HTTP and return the HTML code of the page:
[user@cl05]$telnet richardbuz.de 80 Trying 2a00:c760:83:def:aced:ffff:b921:361f... Connected to richardbuz.de. Escape character is '^]'. GET / HTTP/1.1 HOST: richardbuz.de HTTP/1.1 301 Moved Permanently Date: Fri, 25 Aug 2017 08:12:53 GMT Server: Apache X-Content-Type-Options: nosniff Location: https://richardbuz.de/ Cache-Control: max-age=1209600 Expires: Fri, 08 Sep 2017 08:12:53 GMT Content-Length: 230 Content-Type: text/html; charset=iso-8859-1 <!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN"> <html><head> <title>301 Moved Permanently</title> </head><body> <h1>Moved Permanently</h1> <p>The document has moved <a href="https://richardbuz.de/">here</a>.</p> </body></html> Connection closed by foreign host.
- Hypertext Transfer Protocol (en.wikipedia.org)