BTEC FPT INTERNATIONAL COLLEGE INFORMATION TECHNOLOGY ASSIGNMENT 1 UNIT WEBSITE DESIGN DEVELOPMENT STUDENT NGUYEN TRINH ANH TUAN CLASS IT05102 STUDENT ID BD00096 SUPERVISOR NGUYEN HOANG ANH VU DANAN.
FRONT SHEET
CONTENT
I IDENTIFY THE PURPOSE AND TYPES OF DNS, INCLUDING EXPLANATIONS ON HOW
DOMAIN NAMES ARE ORGANISED AND MANAGED (P1)
Website, also known as website, is a collection of sub-sites, including text, images, videos, flash, etc WEBSITE is only located in a domain name or subdomain hosted on servers running online on the World Wide transmission of the Internet
To easily visualize how a website works, you can refer to the diagram below (as if the website is installed on a separate server)
First, the user enters the browser an address of the form: https://hocban.vn, actually you just need to type "lapo.vn" and the browser will understand and change it to the link above
The browser sends a request to the DNS server
The DNS system returns the results of the domain name analysis in the sent link, which is lapo.vn, it has a server address of 210.212.143.153 (this is already assigned at registration, the DNS server just needs to remember)
After receiving the IP address - where to get the data, the browser will find the received IP address - the server containing the website content
The web server receives the request to retrieve the website content and it sends a set of files including HTML, CSS , other multimedia files such as audio, images (if any) to the browser;
The browser "translates" the files that the server has sent into the web page we see on the screen
Figure 2How the website works
A domain name is the name of a website operating on the internet, acting as a static, fixed address Just like your home address or zip code helps satellite routers navigate your goods, a browser needs a domain name to navigate to your website (web server)
How the domain names are organised and managed?
The operator of the domain name organization is responsible for maintaining administrative data for top-level domains or lower-level domains This unit is licensed to operate through ICANN
The domain management organization will have the authority to manage the top-level domains, and each organization manages the administrative data for its own domain names The management includes container files that contain nameserver addresses and information about domain name registrants
Domain name organizations need to define requirements for the registration of private domain names so that they can use their domain extensions
502 Bad GatewayUnable to reach the origin service The service may be down or it may not be responding to traffic from cloudflared
Figure 4How the domain names are organised and managed
What is Domain Name System?
502 Bad GatewayUnable to reach the origin service The service may be down or it may not be responding to traffic from cloudflared
502 Bad GatewayUnable to reach the origin service The service may be down or it may not be responding to traffic from cloudflared
Figure 5What is Domain Name System o Purpose and type of DNS
The Domain Name System (DNS) is a directory of names that matches with numbers, the numbers are the IP addresses which computers use to communicate with each other The DNS is a protocol which uses the TCP/IP protocol set It helps convert URLs into IP addresses that computers use to identify each other on a network, it is a system that matches names with numbers like a phonebook does With a DNS you do not need to have the IP address of everyone, you connect to a Domain name server, which holds a large database of domain names and translates them to IP addresses 1 So, when you type in a website like www.bbc.co.uk for example, your internet service provider will request the DNS linked with the domain name and then translates it into an IP address that a computer understands then will direct you to the correct website If you have previously visited the website, the computer will first check the cache to see if it has already visited the website before, if not it will do a DNS query to find the website
A resolver is the first stop in a DNS query, this acts as the middle link between the client and a DNS nameserver, once a DNS query has been sent from the client a recursive resolver will bring back cached data if it is found in the cache, or it will send a request to a root nameserver, then another request to a TLD (Top Level Domain) nameserver and then a last request to an authoritative nameserver If the recursive resolver does not have the website that is requested in its cache, then it will go through the process of getting the IP address of the website wanted and return it It will then store this IP address in its memory for a period time The period of time that it is stored in the memory is chosen by the owner of the domain by using a setting called time to live 2 , in which how long the website stays in the cache’s memory for
The iterative DNS query will query a DNS server for information on a website, the user will enter a website they are trying to find and then the resolver may provide an answer from the cached memory or will ask another DNS server if they have the answer by returning the address of that DNS server, if it cannot return a definitive answer it will ask the next server The query will start at the root server and then go down the levels according to its referrals that it receives
The root name server for the DNS records is a server that has a big role in the translating of a domain name into an IP address for a computer, they answer requests made in the root zone of the DNS The servers can answer queries records which are cached in the root zone They can also divert other requests made onto the TLD server
TLD (Top Level Domain) nameserver
The TLD nameserver is referring to the last part of a domain name, the part after the dot TLDs made up into two categories, a country TLD and industries TLD For example FR for France and GOV for governments websites The TLD is the highest level of domain names in the root zone of the DNS for the internet For the other domains in lower levels, it is the last section of the domain name 1 The managing of the TLD nameservers is take care of by the IANA (Internet Assigned Numbers Authority) which is a part of the organisation ICANN
An authoritative nameserver provides answers to an original DNS query It does not provide answers of websites from the cached memory 3 The Authoritative nameserver provides answers to the recursive DNS nameservers with IP mapping of the website (or other server) searched for The authoritative name server holds the records for domain names, these can be either A, CNAME, MX, NS, SOA or TXT records An example could be if a DNS server in a network has stored a record for a website for