Project 2

Domain Name System Protocol

Table of Contents

1. Part I : DNS configuration
   • DNS, role & functions
   • different DNS servers
   • DNS server’s configuration steps
   • Configure the named.conf
   • Create and configure zone files
   • Verify the configuration
   • Configure the DNS Client
   • Configure primary and secondary DNS servers
   • primary DNS server
   • secondary DNS server
   • Test the configuration by stopping the master DNS
2. Part II : DDNS configuration
   • Configure the DDNS server
   • Install the necessary packages
   • Configure the forward and reverse zones
   • Configure the client
   • Verify the configuration
3. Part III : DDNS and DMZ

Part-I

DNS-role-functions

What is DNS?

The Domain Name System (DNS) is the phonebook of the Internet. Humans access information online through domain names, like nytimes.com or espn.com. Web browsers interact > through Internet Protocol (IP) addresses. DNS translates domain names to IP addresses so browsers can load Internet resources.

Each device connected to the Internet has a unique IP address which other machines use to find the device. DNS servers eliminate the need for humans to memorize IP addresses > such as 192.168.1.1 (in IPv4), or more complex newer alphanumeric IP addresses such as 2400:cb00:2048:1::c629:d7a2 (in IPv6).

How does DNS work?

The process of DNS resolution involves converting a hostname (such as www.example.com) into a computer-friendly IP address (such as 192.168.1.1). An IP address is given to > each device on the Internet, and that address is necessary to find the appropriate Internet device - like a street address is used to find a particular home. When a user wants > to load a webpage, a translation must occur between what a user types into their web browser (example.com) and the machine-friendly address necessary to locate the example.com > webpage.

In order to understand the process behind the DNS resolution, it’s important to learn about the different hardware components a DNS query must pass between. For the web > browser, the DNS lookup occurs "behind the scenes" and requires no interaction from the user’s computer apart from the initial request.

There are 4 DNS servers involved in loading a webpage:

• DNS recursor - The recursor can be thought of as a librarian who is asked to go find a particular book somewhere in a library. The DNS recursor is a server designed to > receive queries from client machines through applications such as web browsers. Typically the recursor is then responsible for making additional requests in order to satisfy > the client’s DNS query.

• Root nameserver - The root server is the first step in translating (resolving) human readable host names into IP addresses. It can be thought of like an index in a > library that points to different racks of books - typically it serves as a reference to other more specific locations.

• TLD nameserver - The top level domain server (TLD) can be thought of as a specific rack of books in a library. This nameserver is the next step in the search for a > specific IP address, and it hosts the last portion of a hostname (In example.com, the TLD server is “com”).

• Authoritative nameserver - This final nameserver can be thought of as a dictionary on a rack of books, in which a specific name can be translated into its definition. > The authoritative nameserver is the last stop in the nameserver query. If the authoritative name server has access to the requested record, it will return the IP address for > the requested hostname back to the DNS Recursor (the librarian) that made the initial request.

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different-DNS-servers

The 8 steps in a DNS lookup:

- 1.- A user types ‘example.com’ into a web browser and the query travels into the Internet and is received by a DNS recursive resolver.

- 2.- The resolver then queries a DNS root nameserver (.).

- 3.- The root server then responds to the resolver with the address of a Top Level Domain (TLD) DNS server (such as .com or .net), which stores the information for its domains. When searching for example.com, our request is pointed toward the .com TLD.

- 4.- The resolver then makes a request to the .com TLD.

- 5.- The TLD server then responds with the IP address of the domain’s nameserver, example.com.

- 6.- Lastly, the recursive resolver sends a query to the domain’s nameserver.

- 7.- The IP address for example.com is then returned to the resolver from the nameserver.

- 8.- The DNS resolver then responds to the web browser with the IP address of the domain requested initially.

Once the 8 steps of the DNS lookup have returned the IP address for example.com, the browser is able to make the request for the web page:

+ 9.+ The browser makes a HTTP request to the IP address.

+ 10.+ The server at that IP returns the webpage to be rendered in the browser (step 10).

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DNS-configuration-steps

Configure-the-named

configure-zone-files

Verify-the-configuration

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Configure-the-DNS-Client

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Configure-primary-and-secondary-DNS-servers

primary-DNS-server

secondary-DNS-server

Test-the-configuration

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Part-II

Configure-the-DDNS-server

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Install-the-necessary-packages

Configure-the-forward-and-reverse-zones

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Configure-the-client

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Verify-the-configuration

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Part-III

Project description:

• The goal is to set up a DNS server on a demilitarized zone, based on the delegation between two DNS servers (parent server and child server).The network diagram is as follows:

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Out Team - AIT EL KADI Ilyas - AZIZ Oussama

Project Link: https://github.com/IlyasKadi/Domain-Name-System-Protocol

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