Please Whitelist This Site?

I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)

If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.

If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK.

Thanks for your understanding!

Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide


NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.

The Book is Here... and Now On Sale!

Read offline with no ads or diagram watermarks!
The TCP/IP Guide

Custom Search







Table Of Contents  The TCP/IP Guide
 9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)
      9  TCP/IP Key Applications and Application Protocols
           9  TCP/IP File and Message Transfer Applications and Protocols (FTP, TFTP, Electronic Mail, USENET, HTTP/WWW, Gopher)
                9  TCP/IP World Wide Web (WWW, "The Web") and the Hypertext Transfer Protocol (HTTP)
                     9  TCP/IP Hypertext Transfer Protocol (HTTP)
                          9  HTTP Messages, Message Formats, Methods and Status Codes

Previous Topic/Section
HTTP Methods
Previous Page
Pages in Current Topic/Section
1
2
34
Next Page
HTTP Message Headers
Next Topic/Section

HTTP Status Code Format, Status Codes and Reason Phrases
(Page 2 of 4)

Status Code Format

HTTP status codes are three digits in length and follow a particular format where the first digit has particular significance. Unlike FTP and the others, the second digit does not stand for a functional grouping; the second and third digits together just make 100 different options for each of the categories indicated by the first digit. Thus, the general form of an HTTP status code is “xyy”, where the first digit, “x”, is specified as given in Table 274.


Table 274: HTTP Status Code Format: First Digit Interpretation

Status Code Format

Meaning

Description

1yy

Informational Message

Provides general information; does not indicate success or failure of a request.

2yy

Success

The method was received, understood and accepted by the server.

3yy

Redirection

The request did not fail outright, but additional action is needed before it can be successfully completed.

4yy

Client Error

The request was invalid, contained bad syntax or could not be completed for some other reason that the server believes was the client's fault.

5yy

Server Error

The request was valid but the server was unable to complete it due to a problem of its own.


In each of these five groups, the code where “yy” is “00” is defined as a “generic” status code for that group, while other two-digit combinations are more specific responses. For example, “404” is the well-known specific error message that means the requested resource was not found by the server, while “400” is the less specific “bad request” error. This system was set up to allow the definition of new status codes that certain clients might not comprehend. If a client receives a strange code, it just treats it as the equivalent of the generic response in the appropriate category. So if a server response starts with the code “491” and the client has no idea what this is, it just treats it as a 400 “bad request” reply.

Reason Phrases

The reason phrase is a text string that provides a more meaningful description of the error for people who are bad at remembering what cryptic codes stand for (which would be most of us!) The HTTP standard includes “sample” reason phrases for each status code, but these can be customized by the administrators of a server if desired. When a server returns a more detailed HTML error message in the body of its response message, the reason phrase is often used for the “title” tag in that message body.

Key Concept: Each HTTP response includes both a numeric status code and a text reason phrase, both of which indicate the disposition of the corresponding client request. The numeric code allows software programs to easily interpret the results of a request, while the text phrase provides more useful information to human users. HTTP status codes are three digits in length, with the first digit indicating the general class of the reply.



Previous Topic/Section
HTTP Methods
Previous Page
Pages in Current Topic/Section
1
2
34
Next Page
HTTP Message Headers
Next Topic/Section

If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $



Home - Table Of Contents - Contact Us

The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005

© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.