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HTTP Help: How to test HTTP using Telnet
Telnet is a long-time favorite for troubleshooting connection issues. It can be used to attempt to connect to a server on a given port.
Generally you can quickly ascertain whether something is "listening" on the remote side--which will confirm that (1) you can get to the remote server
from your test box, and (2) that a server is running and bound to the specified port you requested.
More specifically, telnet can be used to test HTTP scenarios, effectively stripping through all the friendly layers a browser usually hides from web visitor eyes.
Troubleshooting HTTP using telnet is a great way to review exactly what is getting returned to your browser during a web request for a particular url.
This allows you to see headers and collect other information related to the web server.
Need a good HTTP troubleshooting reference? Here are some
HTTP resources.
Here is a simple example making an HTTP 1.1 request. First, get to a command prompt. For example, if you are using Windows, Start -> Run -> cmd .
(Though if you are using Windows, you may want to use something like CYGWIN, or Putty rather than the DOS prompt.)
INPUT:
>telnet www.esqsoft.globalservers.com 80
Note: this launches telnet and tells it to look up and connect to the server for "www.esqsoft.globalservers.com" on port 80.
OUTPUT:
Trying 64.136.56.122...
Connected to www.esqsoft.globalservers.com.
Escape character is '^]'.
INPUT:
GET /index.htm HTTP/1.1
host: www.esqsoft.globalservers.com
Notes:
1) no OS cursor caret, the connection is open so you just get a blank line waiting for input.
2) need to hit <enter> twice after the "host:"
OUTPUT:
HTTP/1.1 200 OK
Date: Mon, 18 Apr 2005 16:38:00 GMT
Server: Apache/1.3.27 (Unix) (Red-Hat/Linux) mod_ssl/2.8.12 OpenSSL/0.9.6 PHP/4.1.2 mod_perl/1.27 FrontPage/5.0.2.2623
Last-Modified: Thu, 01 Jul 2004 01:16:05 GMT
ETag: "158e008c-182c-40e365d5"
Accept-Ranges: bytes
Content-Length: 6188
Connection: close
Content-Type: text/html
...
...lots of HTML code here...
Connection closed by foreign host.
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Additional keywords: troubleshooting, http, telnet
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