8.1.3.3 Packet Tracer – Configuring DHCPv4 Using Cisco IOS

Last Updated on March 23, 2018 by Admin

8.1.3.3 Packet Tracer – Configuring DHCPv4 Using Cisco IOS

Packet Tracer – Configuring DHCP Using Cisco IOS (Answer Version)

Answer Note: Red font color or Gray highlights indicate text that appears in the Answer copy only.

Topology

Addressing Table

Device	Interface	IPv4 Address	Subnet Mask	Default Gateway
R1	G0/0	192.168.10.1	255.255.255.0	N/A
	S0/0/0	10.1.1.1	255.255.255.252	N/A
R2	G0/0	192.168.20.1	255.255.255.0	N/A
	G0/1	DHCP Assigned	DHCP Assigned	N/A
	S0/0/0	10.1.1.2	255.255.255.252	N/A
	S0/0/1	10.2.2.2	255.255.255.252	N/A
R3	G0/0	192.168.30.1	255.255.255.0	N/A
	S0/0/1	10.2.2.1	255.255.255.0	N/A
PC1	NIC	DHCP Assigned	DHCP Assigned	DHCP Assigned
PC2	NIC	DHCP Assigned	DHCP Assigned	DHCP Assigned
DNS Server	NIC	192.168.20.254	255.255.255.0	192.168.20.1

Objectives

Part 1: Configure a Router as a DHCP Server

Part 2: Configure DHCP Relay

Part 3: Configure a Router as a DHCP Client

Part 4: Verify DHCP and Connectivity

Scenario

A dedicated DHCP server is scalable and relatively easy to manage, but can be costly to have one at every location in a network. However, a Cisco router can be configured to provide DHCP services without the need for a dedicated server. As the network technician for your company, you are tasked with configuring a Cisco router as a DHCP server to provide dynamic allocation of addresses to clients on the network. You are also required to configure the edge router as a DHCP client so that it receives an IP address from the ISP network.

Part 1: Configure a Router as a DHCP Server

Step 1: Configure the excluded IPv4 addresses.

Configure R2 to exclude the first 10 addresses from the R1 and R3 LANs. All other addresses should be available in the DHCP address pool.

R2(config)# ip dhcp excluded-address 192.168.10.1 192.168.10.10

R2(config)# ip dhcp excluded-address 192.168.30.1 192.168.30.10

Step 2: Create a DHCP pool on R2 for the R1 LAN.

1. Create a DHCP pool named R1-LAN (case-sensitive).
   • R2(config)# ip dhcp pool R1-LAN
2. Configure the DHCP pool to include the network address, the default gateway, and the IP address of the DNS server.
   • R2(dhcp-config)# network 192.168.10.0 255.255.255.0
   • R2(dhcp-config)# default-router 192.168.10.1
   • R2(dhcp-config)# dns-server 192.168.20.254

Step 3: Create a DHCP pool on R2 for the R3 LAN.

1. Create a DHCP pool named R3-LAN (case-sensitive).
   • R2(config)# ip dh pool R3-LAN
2. Configure the DHCP pool to include the network address, the default gateway, and the IP address of the DNS server.
   • R2(dhcp-config)# network 192.168.30.0 255.255.255.0
   • R2(dhcp-config)# default-router 192.168.30.1
   • R2(dhcp-config)# dns-server 192.168.20.254

Part 2: Configure DHCP Relay

Step 1: Configure R1 and R3 as a DHCP relay agent.

!R1
R1(config)# interface g0/0
R1(config-if)# ip helper-address 10.1.1.2
!R3
R3(config)# interface g0/0
R3(config-if)# ip helper-address 10.2.2.2

Step 2: Set PC1 and PC2 to receive IP addressing information from DHCP.

Part 3: Configure R2 as a DHCP Client

1. Step 1: Configure the Gigabit Ethernet 0/1 interface on R2 to receive IP addressing from DHCP and activate the interface.
   • R2(config)# interface g0/1
   • R2(config-if)# ip address dhcp
   • R2(config-if)# no shutdown
   • Note: Use Packet Tracer’s Fast Forward Time feature to speed up the process or wait until R2 forms an EIGRP adjacency with the ISP router.
2. Use the show ip interface brief command to verify that R2 received an IP address from DHCP.

Part 4: Verify DHCP and Connectivity

Step 1: Verify DHCP bindings.

R2# show ip dhcp binding

IP address               Client-ID/                          Lease expiration                     Type

                                  Hardware address

192.168.10.11         0002.4AA5.1470               —                                                Automatic

192.168.30.11        0004.9A97.2535                —                                               Automatic

Step 2: Verify configurations.

Verify that PC1 and PC2 can now ping each other and all other devices.