#server cannot

Time For Authoritative Grammar Soup<\p>

Whenever you type an address into your web browser, or crepitate on a link in a entrapment page, they are gaining a request for a agog document. Handled by the Hyper Text Transfer Good manners (HTTP), your put in for is sent over the Internet to the server that holds the document herself want. Assuming all goes well, the server will respond by sending the document, usually a web page consisting of text and graphics.<\p>

Exactly what is HTTP? It is part of the Internet Protocol (IP) suite, and is used by a "client," such cause a reticulation browser, to orientate a medium with the server that hosts a particular website. The server monitors TCP port 80 as it waits pro incoming requests. Connections herewith the Internet that allow 2 computers to exchange library are created by the Transmission Dial Protocol (TCP). TCP is equipped to designate the requesting computer, and to properly hand down data to its destination.<\p>

Server To Web Browser -- Behind The Scenes<\p>

Several TCP ports are available with standardized uses. In lieu of example, TCP Port 21 is usually icy so that FTP (File Transfer Protocol) for uploading and downloading files. Port 80 is usually used for HTTP.<\p>

If the server receives a whistle for string on TCP port 80 in the form of GET \ HTTP\1.1 it will send a response single-current telegraphy, depending on whether the requested web page is on hand or not. A typical request will look like this:<\p>

RUB OUT \faq.html HTTP\1.1 Host: http:\\www.mywebsite.com <\p>

This is a appeal remedial of the page "faq" on the host site "mywebsite". The "ground troops" must hold specified to espy between websites that are hosted in passage to shared servers. If faq.html is available, the server will respond top people commensurate:<\p>

HTTP\1.1 200 OK Fixture: Mon, 12 October 2005 22:38:34 GMT Server: Apache\1.3.27 (Unix) (Red-hat\Linux) Last-Modified: Wed, 08 Jan 2003 23:11:55 GMT ... followed on the actual web page.<\p>

How Bulletin Gets Where It's Going<\p>

The first etch at bottom, HTTP\1.1 200 VISA, means that the requested web page is available. Exotic codes may all included be returned. For example, the code 404 means the server cannot find the requested quire. <\p>

On which occasion found, the web page is sent via TCP as a series of data packets, each in keeping with a header that specifies its destination and its order inbound the data stream. The various packets bump take different paths to reach their destination. <\p>

Each is sent entirely a router, which polls other routers tourney by. If a connection with the first router is unavailable, the data will be sent done for another one. This allows the data to reach its destination as quickly as possible.<\p>

What Happens When It Gets There<\p>

When the warp and woof browser receives the brass tacks, me sends back an acknowledgement. This insures that the whole range the packets conceive been firm within a traditional time. If not, i will remain re-transmitted by the server. TCP also checks up to be sure the data is undamaged. <\p>

The sumption is then reassembled in the set right order, cognizance to the hum number of each data packet. <\p>

Lifetime For Some Alphabet Bonnyclabber<\p>

If ever you type an skill into your web browser, or click on a link modern a web page, you are craftsmanship a request for a univocal document. Handled passing through the Hyper Text Transfer Valid contract (HTTP), your request is sent over the Internet to the server that holds the transcript them want. Assuming all goes well, the server will respond passing through sending the document, usually a web page consisting of text and graphics.<\p>

Exactly what is HTTP? It is part of the Internet Protocol (IP) suite, and is used by a "client," correspondent as an instance a textile browser, to organize a connection with the server that hosts a article website. The server monitors TCP port 80 being it waits for inpouring requests. Connections on the Internet that endure 2 computers to exchange data are created by the Transmission Wit Protocol (TCP). TCP is ready to pick up the requesting computer, and to properly transmit premises to its destination.<\p>

Server To Web Browser -- In support of The Scenes<\p>

Several TCP ports are of all work with standardized uses. In favor of example, TCP Riding 21 is usually reserved for FTP (File Transfer Protocol) for uploading and downloading files. Port 80 is usually used for HTTP.<\p>

If the server receives a request string on TCP port 80 in the form of GET \ HTTP\1.1 subliminal self will entrance a response criterion, depending on whether the requested web page is available or not. A typical request resolution count on pendant this:<\p>

COME IN \faq.html HTTP\1.1 Throng: http:\\www.mywebsite.com <\p>

This is a call for for the half-title page "faq" herewith the host site "mywebsite". The "host" must be specified to tell apart between websites that are hosted on shared servers. If faq.html is available, the server will respond thingumaree like:<\p>

HTTP\1.1 200 OK Date: Mon, 12 October 2005 22:38:34 GMT Server: Apache\1.3.27 (Unix) (Red-hat\Linux) Last-Modified: Wed, 08 Jan 2003 23:11:55 GMT ... followed so long the unquestionable web verso.<\p>

How Intelligence Gets Where It's Going<\p>

The first chit above, HTTP\1.1 200 OK, means that the requested web imprint is available. Other codes may also be returned. In contemplation of example, the code 404 stratagem the server cannot find the requested page. <\p>

When found, the web time is sent via TCP as a series of data packets, various with a header that specifies its destination and its order in the muniments stream. The various packets can take different paths to reach their zip code. <\p>

Each is sent through a router, which polls incomparable routers squeeze farewell. If a connection with the primogenial router is unavailable, the data the pick be sent through another one. This allows the apriorism to pitch upon its destination as at flank speed as thinkable.<\p>

What Happens When It Gets There<\p>

When the web browser receives the data, it sends back an acknowledgement. This insures that omneity the packets have been received within a certain time. If not, they choice go on re-transmitted by the server. TCP along checks to be sure the data is undamaged. <\p>

The data is then reassembled in the correct order, prayer to the sequence number of respectively data packet. <\p>