Configuring DHCP for IPv6 Stateless Address Auto-Configuration (SLAAC) is essential for enabling automatic IP address configuration in IPv6 networks. This guide will walk you through the steps to configure DHCP for IPv6 SLAAC on a Cisco router. We will use specific commands and configurations to ensure a smooth setup process.
What is IPv6 Stateless Address Auto-Configuration (SLAAC)?
SLAAC allows devices on an IPv6 network to automatically configure their own IP addresses based on router advertisements. Unlike DHCPv4, SLAAC doesn't require a central server to assign IP addresses. Instead, it relies on the router to provide network prefixes and configuration information, which the devices then use to generate their own addresses.
Prerequisites
Ensure that IPv6 routing is enabled on your Cisco router.
Have an IPv6 network prefix available for configuration.
Know the IPv6 address of your DNS server (if applicable).
Step-by-Step Configuration
1. Enable IPv6 Unicast Routing
First, we need to enable IPv6 routing on the router to ensure it can handle IPv6 traffic.
R1(config)# ipv6 unicast routing
2. Create a DHCPv6 Pool
Next, we create a DHCPv6 pool to define the addresses and DNS information that will be provided to clients.
R1(config)# ipv6 dhcp pool LAN-10-STATELESS
R1(dhcpv6-config)# dns-server 2001:345:ACAD:F::5
R1(dhcpv6-config)# domain-name cisco.com
In this configuration:
LAN-10-STATELESS is the name of the DHCPv6 pool.
2001:345:ACAD:F::5 is the IPv6 address of the DNS server.
cisco.com is an optional domain name provided to clients.
3. Configure the Interface with IPv6 Address and DHCP
We now configure the interface that will be used to connect to the IPv6 network. This involves setting an IPv6 address and linking it to the DHCPv6 pool we created.
R1(config)# interface g1/1
R1(config-if)# ipv6 address 2001:A1B5:C13:10::1/64
R1(config-if)# ipv6 dhcp server LAN-10-STATELESS
R1(config-if)# ipv6 nd other-config-flag
In this step:
g1/1 is the interface being configured.
2001:A1B5:C13:10::1/64 is the IPv6 address assigned to the interface.
LAN-10-STATELESS is the DHCPv6 pool used for configuration information.
The ipv6 nd other-config-flag command enables the Neighbor Discovery protocol to inform clients to use DHCPv6 for additional configuration information like DNS.
Additional Configuration
For more advanced configurations, you may need to adjust additional settings based on your network requirements. Here are some additional commands you might find useful:
To specify the prefix to be advertised, you can use:
R1(config-if)# ipv6 nd prefix 2001:A1B5:C13:10::/64
To limit the number of DHCP clients, you can set a limit in the DHCP pool:
R1(dhcpv6-config)# address prefix 2001:A1B5:C13:10::/64 lifetime 300 600
Verifying Configuration
After configuring the router, it's crucial to verify the setup to ensure everything is working as expected. Use the following commands to check the status:
R1# show ipv6 interface g1/1
R1# show ipv6 dhcp pool LAN-10-STATELESS
R1# show ipv6 neighbors
These commands will provide information about the interface configuration, the DHCPv6 pool status, and the IPv6 neighbors detected on the network.
Configuring DHCP for IPv6 Stateless Address Auto-Configuration (SLAAC) on a Cisco router is a straightforward process that involves enabling IPv6 routing, creating a DHCPv6 pool, and configuring the interface with the necessary settings. By following this guide, you can ensure that your IPv6 network is set up to automatically configure IP addresses for devices, simplifying network management and reducing administrative overhead.
Remember, the key to a successful configuration is verifying each step to ensure that all settings are correctly applied and functioning as intended. Happy networking!
For more detailed information on each command and additional configuration options, refer to the official Cisco documentation or contact your network administrator.
