NET323 D: NETWORKS PROTOCOLS

Transcription

1 1 NET323 D: NETWORKS PROTOCOLS Networks and Communication Systems Department TA. Anfal AlHazzaa Lab # 8: DNS (Domain Name System)

2 Lab Objectives 2 To understand how DNS works

3 Lab Content 3 Introduction to Application Layer What is Server? What is Client? What is DNS (Domain Name System)? Scenario # 1 (Accessing Web server without DNS) Scenario # 2 (Accessing Web server with DNS)

4 Introduction to Application layer 4 There are several applications in the application layer of the Internet model that follow the client/server paradigm. The client/server programs can be divided into two categories: Application that directly used by the user, such as , Application that support other application programs. The Domain Name System (DNS) is a supporting program that is used by other programs such as .

5 What is Server? 5 A server is a computer program or a machine capable of accepting requests from clients and responding to them. Typical computing servers are database servers, file servers, mail servers, print servers, web servers, game servers and DNS server.

6 What is Client? 6 A client is a piece of computer hardware or software that accesses a service made available by a server

7 What is DNS (Domain Name System)? 7 DNS translates Internet domain and host names to IP addresses. DNS automatically converts the names we type in our Web browser address bar to the IP addresses of Web servers hosting those sites. DNS is a supporting program that is used by other programs such as and web browser

8 How DNS works? 8

9 Scenario # 1: Accessing Web server without DNS 9 1. Create a simple LAN contains two clients and web server 2. Access the web server using the IP address of the web server

10 Step 1 )Creating the network( Open The Packet tracer 2. Add two PCs and one Server-PT to your workspace 3. Rename them and set their IPs as follows: Device Type Device name IP Mask PC Client PC Client Server Web Server

11 Step 1 )Creating the network( cont Drag Switch-PT to the workspace 5. Using Copper Straight-through cable connect the end devices to the switch as follows: Device name Switch ports Client 1 Fast Ethernet 0/1 Client 2 Fast Ethernet 1/1 Web Server Fast Ethernet 2/1

12 2 1 Step 2 ) Configuring the web server( 12 Click on the Web Server config tab choose HTTP 3. Turn the HTTP and HTTPS on The page name The content of the home page To go to previous or next page To add new page

13 Step 3 ) Accessing the web server from client 1( 13 Click on client 1 desktop tab web browser 1 2

14 Step 3 )Accessing the web server from client 1( cont. 14 To access the webpages which stored in the web server type the IP address of the web server click on GO button

15 Scenario # 2: Accessing Web server with DNS Create a simple LAN contains two client, web server and DNS server 2. Use DNS server to access the web server 3. Capture and analyze DNS request and replay

16 Step 1 )Creating the network( Add server-pt to the previous topology 2. Rename the server and assign its IP as follows Device Type PC name IP Mask Server DNS server Using Copper Straight-through cable connect the DNS server to the switch as follows: Device name Switch ports DNS Server Fast Ethernet 3/1

17 2 1 Step 2 ( Configuring DNS server ) 17 Click on the DNS Server config tab choose DNS 3. Turn on the DNS 4. Type the domain name of the web server 5. Choose A record 6. Type the IP address of the web server and then click on Add button

18 Step 3 ( Configuring DNS on the end devices) 18 Click on Client 1 desktop tab IP configuration Type the IP of the DNS server Repeat the same configuration on all end devices

19 Step 4 ( Accessing the web server from client 1) 19 Click on Client 1 desktop tab web browser 1 2

20 Step 4 ( Accessing the web server from client 1) cont. 20 To access the webpages which stored in the web server type the domain name of the web server click on GO button

21 Step 5 (Capturing and analyzing DNS message) Switch to Simulation mode. 2. In the Simulation Panel, change Edit Filters to display only DNS and HTTP. 3. Click Client 1 and click the Desktop tab Web Browser. 4. In the URL field, enter pnu.edu.sa and click Go. 5. Envelopes (PDUs) will appear in the simulation window. 6. Minimize, but do not close, the Client 1configuration window. 7. Run the simulation.

22 References 22 Cisco Packet Tracer Help Data Communication and Networking, by Behrouz A Forouzan, McGraw Hill, Server (computing). (2015, November 13). Retrieved 2015, from Client (computing). (2015, September 11). Retrieved 2015, from Domain Name System (DNS). (n.d.). Retrieved 2015, from