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
Every request sent by an HTTP client causes one (or more) responses to be returned by the server that receives it. As we saw in the topic describing the response message format, the first line of the response is a status line that contains a summary of the results of processing the request. The purpose of this line is to communicate quickly whether or not the request was successful, and why.
HTTP status lines contain both a numeric status code and a text reason phrase. The idea behind this was taken directly from earlier application layer protocols such as FTP, SMTP and NNTP. The reason for having both a number and a text string is that computers can more easily “understand” the results of a request by looking at a number, and can then quickly respond accordingly. Humans, on the other hand, find numbers cryptic and text descriptions easier to comprehend. (The topic on FTP reply codes discusses more completely the reasons why numeric reply codes are used in addition to descriptive text.)