Week_Six_Revision

Week_Six_Revision

1. What software should be used to serve web pages over the internet?

   • - Apache Web Server Web Server:  - A network computer that provides web pages to clients computer on request.   - This is achieved by receiving HTTP requests from clients and processing and replying to these request. Web Client:  - Uses a client web browser application to retrieve and present information from WWW.  - This uses HTML web pages (Hyper Text MarkUp Language) by using TCP/IP protocols.  

2. Describe how the HTTP protocol works

   • - Uses the HTTP protocol and the TCP/IP Application Layer Protocol.  - Operates on a Request - Response Protocol  1. The client submits a HTTP request to the server using TCP to establish connection.   2. The server then returns a response message to the client:   2.1; Completion Status    2.2; Requested Status
   • HTTP - Request
     • Once the client has submitted the request for resource from the server, HTTP methods are used to indicate desired action on the identified resource.  I.E - The server interprets and processes the request.  1. GET - Used to RETRIEVE data   2. POST - Used to SEND data  3. HEAD - Used to retrieve META-DATA
   • HTTP - Response
     • The server then interprets and processes the request.  IF requested resource =  - Static Resource; Server copies resource in order to return it to the client (HTML Page).  - Dynamic Resource; Server performs execution of resources and copies result in order to return it to the client (PHP script).  

3. What is a Virtual Host

   • - This is used to support multiple web sites on ONE physical server.  - ALL virtual hosts must have their server name resolved on the network.
   • Named-Based Virtual Host
     • - Multiple websites share the same IP address. - Uses ServerName directive to specify the name of the server 
     • To configure Virtual Host the following MUST be specified:  1. ServerName directive  2. DocumentRoot directive   3. Directory directive 
   • IP-Based Virtual Host
     • - Multiple IP addresses for a single machine

4. What is the key role of DNS?

   • - To decentralize administration.  - It is a distributed and hierarchical database that enables local DNS management control.  - Each level of hierarchy is separated by dots in the domain name. For Example .gov = U.S government domain. 

5. What is a Name Server?

   • - This is a central database that translates names to IP addresses (or visa versa). -It simplified network management but only worked on local networks, NOT resources on the internet. 

6. What is a DNS Zone?

   • - This is a portion of the DNS namespace that been delegated to other servers / administrators.  - The zone file stores data for a zone.

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