June 05, 2006
From Registering A Domain To Getting It Online (Part 3)
After you have opened an account with a web host and set the DNS you can start uploading your web pages. The most common way to do this is to use FTP (File Transfer Protocol) software but there are also some other options.
Your host will also tell you the location where files should be uploaded. Your account will probably have two main folders in the root directory – public_html and www. Your web pages should be uploaded to the public_html folder. The www folder is a mirror folder which allows people to find your site by using either www.mysite.com or mysite.com.
You may have to adjust a few settings in your FTP software to upload files correctly. For example, if you are using a firewall on your computer you should set the transfer method to passive. If you are using a proxy you will have to adjust the proxy settings.
Files can be sent or received in either binary or ASCII mode. If they are transferred using the incorrect mode they may end up with errors on completion of the transfer. Your FTP software may try to determine which mode to use by examining the contents of the files, or you may have to manually specify the transfer mode. Files that should be sent in ASCII mode include HTML (and variants like HTM, SHTML, DHTML, etc.) TXT, CGI, C, ASP, JS etc. Basically, any file that can be viewed in a text editor should be transferred in ASCII mode. Binary mode, on the other hand, is used to transfer everything else – graphics, compiled programs, and media files.
Using the FTP software, make a connection to your web server. Browse to the folder where you want to upload files (usually by clicking on the folder icons) and then find the local files you wish to upload. Whole directories or individual files may be uploaded.
You can name most of the pages of your website anything you like, but there is one essential file in each directory – index.html or a variant (index.htm, index.shtml etc). This means that your home page has to use this name. The home page can be viewed by typing http://mywebsite.com or http://mywebsite.com/index.htm. In the first case, if there is no file named index.htm the contents of your root directory will be shown. Without an index file in each directory, anybody who browses to that directory can see all the files there. This presents an enormous security risk as well as exposing private information to public view.
FTP is the most common way to upload files to your website but is by no means the only way. Some web authoring packages have built in transfer methods to automatically upload your entire site or individual pages. Microsoft FrontPage is an example of this type of transfer method. In order to take advantage of it you need to have FrontPage extensions installed on your website. You can request this feature from your web host. Other authoring packages have built-in FTP software so that you can build your site and upload with one familiar interface.
You can also build sites online. Some web hosts give you access to browser controlled software that allows you to lay out web pages. Once you are finished the page is automatically saved to the proper location on your server. This type of web builder is usually available through the control panel of your hosting account.
Posted by WebHost at 11:50 PM | Comments (0)
May 28, 2006
Server to Web Browser – What Happens?
Each time you click on a link in a web page or type an address into your web browser you are making a 'request' for a certain document. That request is handled with the Hyper Text Transfer Protocol (HTTP) and sent over the Internet to the server which holds the document in question. If all goes well the server responds by sending the document -- usually a web page of text and graphics.
Transmission Control Protocol (TCP) is used to create connections between two computers on the Internet so they can exchange data. TCP has provisions for identifying the requesting computer and for transmitting data with time stamps so that it can be reassembled in the correct order once it arrives at its destination.
There are several TCP ports which have standardized uses. TCP port 21, for example, is usually reserved for FTP (File Transfer Protocol) for uploading and downloading files. Port 80 is usually used for HTTP.
If the server receives a request string on TCP port 80 in the form of GET / HTTP/1.1 it will send a response code depending on whether the requested web page is available or not. A typical request goes like this:
GET /faq.html HTTP/1.1
Host: http://www.mywebsite.com
This is a request for http://www.mywebsite.com/faq.html. The 'Host' needs to be specified to distinguish websites which are hosted on shared servers. If faq.html is available the server will respond:
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 by the actual web page.
HTTP/1.1 200 OK means that the requested web page is available. Other codes can also be returned. The code 404, for example, means that the server cannot find the requested page. The web page is sent via TCP as a series of data packets each with a header that specifies its destination and order in the data stream. The various packets can all take different paths to reach their destination. Each is sent through a router which polls other routers which are close by. If a connection with the first router is unavailable the data will be sent through another one.
As the data is received the client (the web browser) sends back an acknowledgement. This ensures that all the packets are received within a certain time. If not, they will be re-transmitted by the server. TCP also checks that the data is undamaged. The data is reassembled in the correct order thanks to the sequence number of each data packet. Voila! The web page appears on your computer screen.
The TCP connection can be kept alive for additional requests from the client. This allows several pages to be requested within a short time period without causing the overhead of opening and closing TCP ports. Either client or server can close the connection at any time.
Posted by WebHost at 01:25 PM | Comments (0)
