NET323 D: NETWORKS PROTOCOLS

Transcription

1 1 NET323 D: NETWORKS PROTOCOLS Networks and Communication Systems Department TA. Anfal AlHazzaa Lab # 9: DHCP (Dynamic Host Dynamic Host Configuration Protocol )

2 Lab Objectives 2 To understand how DHCP works

3 Lab Content 3 What is DHCP? How DHCP works? How to configure DHCP server on the router? Scenario # 1 (DHCP Configuration)

4 What is DHCP? 4 Stands for Dynamic Host Configuration Protocol DHCP is a protocol that automatically assigns a unique IP address to each device that connects to a network. With DHCP, there is no need to manually assign IP addresses to new devices. Therefore, no user configuration is necessary to connect to a DCHP-based network. DHCP is the default protocol used by most routers and networking equipment.

5 How DHCP works? 5 When you connect to a network, your device is considered a client and the router is the server. In order to successfully connect to a network via DHCP, the following steps must take place. 1. When a client detects it has connected to a DHCP server, it sends a DHCPDISCOVER request. 2. If the server accepts the new device, it will send DHCPOFFER message back to the client, which contains the client device's MAC address and the IP address being offered. 3. The client returns a DHCPREQUEST message to the server, confirming it will use the IP address. 4. Finally, the server responds with a DHCPACK acknowledgement message that confirms the client has been given access (or a "lease") for a certain amount of time.

6 How DHCP works? cont. 6

7 How to configure DHCP on the router? 7 DHCP configuration On the global configuration mode, write the follwing command ip dhcp pool [name] network [network address] [mask] default-router [IP address] dns-server [IP address] exit

8 How to configure DHCP on the router? Cont. 8 Command ip dhcp pool [name] network [network address] [mask] default-router [IP address] dns-server [IP address] Exit description To create a DHCP IP address pool for the IP addresses you want to use. *You have to write name of the pool (can be any name ex. Nw1) To specify the network and subnet for the addresses you want to use from the pool. To specify the default router (i.e., default gateway). To specify the IP address of DNS server (optional) To exit Pool Configuration Mode.

9 NOTE 9 If you have more than one networks connect to the router, you have to create a pool for each network.

10 10 [Example] Configuring DHCP( pool for first network) Example : Network address: /8 Network address : /24 ip dhcp pool nw1 network default-router exit

11 11 [Example] Configuring DHCP( pool for second network) Example : Network address: /8 Network address : /24 ip dhcp pool nw2 network default-router exit

12 Scenario # 1 (DHCP Configuration) Create two simple LANs (each LAN contains three devices) 2. Connect the two LANs using a router (as shown in the following figure) 3. Configure DHCP on the routers and PCs 4. Perform a ping between PC 1 and PC 4 in realtime mode

13 Step 1 ( Creating the network ) 13 Create the following topology:

14 Step 2 ( Assigning IPs to router interfaces) 14 Assign the following IPs to the router interfaces: Router 1 : Interface IP Mask Fast Ethernet 0/ Fast Ethernet 1/

15 Step 2 ( Assigning IPs to router interfaces) cont. 15 You have to enter to the CLI of the router by clicking on it and then choose CLI tab 1

16 Router 1 Configuration ( interface f0/0) 16

17 Router 1 Configuration ( interface f1/0) 17

18 Step 3 ( Configuration DHCP on a router ) 18 You have to enter to the CLI of the router by clicking on it and then choose CLI tab 1

19 Step 3 ( Configuration DHCP on a router ) 19 Configuring DHCP( pool for first network)

20 Step 3 ( Configuration DHCP on a router ) 20 Configuring DHCP( pool for second network)

21 Step 4 ( Configuration DHCP on PCs) 21 Click on client 1 desktop tab IP Configuration 1

22 Step 4 ( Configuration DHCP on PCs) cont. 22 Choose DHCP and all IP configuration will appear automatically Repeat the same steps on each PC in the two networks

23 Note 23 You can use the following command to renew DHCP configuration ipconfig /renew You can use the following command to send a DHCPRELEASE message to the DHCP server to release the current DHCP configuration ipconfig /release

24 Step 5 (Performing a ping in realtime mode) 24 Click on PC 1 Desktop tap Command Prompt Write the following command Ping

25 References 25 Cisco Packet Tracer Help DHCP. (2014, August 19). Retrieved 2015, from Davis CCIE, D. (2005, May 5). Configure DHCP on a Cisco router or switch - TechRepublic. Retrieved 2015, from Ipconfig. (n.d.). Retrieved 2015, from