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Advanced Web 2012 Lecture 2 Sean Costain 2012

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Advanced Web2012Lecture 2Sean Costain 2012

How the Web Works - RefreshSean Costain 2012The web is a matrix of servers that handle client requests and deliver the content at a per-request action.

Web ContentSean Costain 2012

Web content is data that is delivered to the end user through web pages.Content is now Dynamic, in that it responds to user actions.Content is normally stored in databasesMySQL, MsSQLAccess of Dynamic content requires advanced languagesPHP, ASP

Web ServerSean Costain 2012A web server is a computer that runs a special service that is designed to handle web requests.

A web request is a data stream that flows on port 80 or port 443. The language of the web is TCP/IP.

The main difference between a pc and a server is the amount of requests that the machine can handle, and its method of supplying the requested information.TCP/IPSean Costain 2012Transmission Control Protocol (TCP) is one of the core protocols of the Internet Protocol Suite. TCP is one of the two original components of the suite, complementing the Internet Protocol (IP), and therefore the entire suite is commonly referred to as TCP/IP.

TCP provides reliable, ordered delivery of a stream of octets from a program on one computer to another program on another computer. TCP is the protocol used by major Internet applications such as the World Wide Web, email, remote administration and file transfer.

Web ServerSean Costain 2012TCP/IP Ports

Port 80 http traffic; the primary port used by the world wide web (www) system. Web servers open this port then listen for incoming connections from web browsers.

Port 443 https traffic; secure web browser communication. Data transferred across such connections are highly resistant to eavesdropping and interception.Port 80Port 443TCP/IPHas 1056 common ports for communicationWeb ServerSean Costain 20122 Main Web servers in the worldApacheIIS (Internet Information Services)

Apache is Open Source and can be run on pretty much any operating system.IIS is proprietary and runs only on the Windows operating system.Both servers do pretty much the same thing, handle client requests and deliver content.

Were using Apache (XAMPP) in this course.Remote ServerSean Costain 2012A remote web server is a server that is not running on the machine you are currently using.

Remote servers are normally production servers, these can come in various formats such as:Dedicated ServersVirtual ServersShared Web SpaceDedicated ServerExpensiveFull ControlAll the hardware is for your use only.Virtual ServerMedium PriceFull Control over VM, not physical configOther user share the same hardwareShared WebCheapControl only over your data.All resources shared with other clients, physical and digital.

Local ServerSean Costain 2012A local web server is a server that is running on the machine you are currently using.

Local servers are normally development servers, these can come in various formats such as:A server your company controlsA desktop machine you usePortable on a USBLocal servers are faster than remote servers as the browser request doesnt have to leave the machine.Communication MethodsSean Costain 2012When it comes to Remote servers, there are a few ways of communicating with the server. This is all dependent on the type of server.Dedicated server : RDP (port 3389), Telnet (port 23), SSH (port 22), FTP (port 21), File upload through the web (port 80)All other server types: FTP (port 21), File upload through the web (port 80)RDP, telnet and SSH all allow for access to manipulate the operating system.FTP and file upload, only manipulate your web files

RDP

FTPCommunication MethodsSean Costain 2012Local servers, on the other hand, are extremely easy to work with.You can just copy over the working files or work directly on them with your web application.Apache stores its web pages in a folder called htdocs.IIS stores its web pages in a folder called wwwroot

Sean Costain 2012