Dynamic Host Configuration Protocol (DHCP) is a network management tool that automatically assigns IP addresses to devices on a network. By implementing DHCP on your Cisco router, you can simplify IP address management for both IPv4 and IPv6 networks. In this guide, we’ll walk you through the steps to configure DHCP for IPv4 and IPv6 address assignment on a Cisco router.
Why Use DHCP?
- IPv4 and IPv6 Address Management: Automates the assignment of IP addresses, reducing manual configuration errors.
- Scalability: Easily supports growing networks with many devices.
- Efficiency: Saves time and effort in managing IP addresses.
- Centralized Control: Provides a single point of management for IP address allocation.
Step 1: Access the Router’s CLI
- Connect to your router via console cable, Telnet, or SSH.
- Enter privileged EXEC mode:CopyRouter> enable Router#
Step 2: Configure DHCP for IPv4
1. Create a DHCP Pool
- Enter global configuration mode:
Router# configure terminal
Router(config)# - Create a DHCP pool for IPv4:
Router(config)# ip dhcp pool LAN_POOL
Router(dhcp-config)#- Replace
LAN_POOL
with a name for your DHCP pool.
- Replace
2. Define the Network and Default Gateway
- Specify the network and subnet mask:
Router(dhcp-config)# network 192.168.1.0 255.255.255.0
- Replace
192.168.1.0
and255.255.255.0
with your network details.
- Replace
- Set the default gateway:
Router(dhcp-config)# default-router 192.168.1.1
- Replace
192.168.1.1
with your router’s interface IP address.
- Replace
3. Configure DNS Servers (Optional)
- Add DNS server addresses:
Router(dhcp-config)# dns-server 8.8.8.8 8.8.4.4
- Replace
8.8.8.8
and8.8.4.4
with your preferred DNS servers.
- Replace
4. Exclude Reserved IP Addresses
- Exclude IP addresses from the DHCP pool (e.g., for static devices):
Router(config)# ip dhcp excluded-address 192.168.1.1 192.168.1.10
- Replace
192.168.1.1
and192.168.1.10
with the range of addresses to exclude.
- Replace
Step 3: Configure DHCP for IPv6
1. Enable IPv6 Routing
- Enable IPv6 routing on the router:
Router(config)# ipv6 unicast-routing
2. Create an IPv6 DHCP Pool
- Create a DHCP pool for IPv6:
Router(config)# ipv6 dhcp pool LAN_POOL_IPV6 Router(config-dhcpv6)#
- Replace
LAN_POOL_IPV6
with a name for your IPv6 DHCP pool.
- Replace
3. Define the IPv6 Network and DNS
- Specify the IPv6 prefix:
Router(config-dhcpv6)# address prefix 2001:db8::/64
- Replace
2001:db8::/64
with your IPv6 network prefix.
- Replace
- Add DNS server addresses:
Router(config-dhcpv6)# dns-server 2001:4860:4860::8888
- Replace
2001:4860:4860::8888
with your preferred IPv6 DNS server.
- Replace
4. Configure the Interface for IPv6 DHCP
- Enter interface configuration mode:
Router(config)# interface GigabitEthernet0/0
Router(config-if)# - Enable IPv6 on the interface:
Router(config-if)# ipv6 enable
- Assign an IPv6 address to the interface:
Router(config-if)# ipv6 address 2001:db8::1/64
- Configure the interface to use the DHCP pool:
Router(config-if)# ipv6 dhcp server LAN_POOL_IPV6
Step 4: Verify the Configuration
- Exit configuration mode:
Router(config-if)# exit
Router(config)# exit
Router# - Verify the IPv4 DHCP pool:
Router# show ip dhcp pool
- Verify the IPv6 DHCP pool:
Router# show ipv6 dhcp pool
Step 5: Test DHCP Functionality
- Connect a device to the network and check if it receives an IP address.
- Use the following commands to verify:
- For IPv4:
Router# show ip dhcp binding
- For IPv6:
Router# show ipv6 dhcp binding
- For IPv4:
Step 6: Save the Configuration
To ensure your changes persist after a reboot:
Router# write memory
or
Router# copy running-config startup-config
Conclusion
Implementing DHCP for IPv4 and IPv6 address assignment on a Cisco router simplifies network management and ensures efficient IP address allocation. By following the steps outlined in this guide, you can configure DHCP to support both IPv4 and IPv6 networks, making your network more scalable and easier to manage.
If you found this guide helpful, feel free to share it with your peers or leave a comment below with your thoughts or questions. Happy networking!
About the Author:

Ali Asad is a network engineer and tech enthusiast with a passion for sharing knowledge about networking, cybersecurity, and IT infrastructure. Follow [Your Blog/Social Media] for more tips and tutorials!