How to Configure DHCPV6 Stateful Auto-configuration (Server and Client )
DHCPv6 Stateful Auto-configuration is a method used in IPv6 networks to assign IP addresses and other network configuration information to devices automatically. Unlike the stateless auto-configuration in IPv6, which allows devices to generate their own addresses using local network information, stateful configuration relies on a DHCPv6 server to provide IP addresses and additional configuration details.
Here are its key aspects:
DHCPv6 Server Role: A DHCPv6 server centrally manages and assigns IPv6 addresses and other configuration details to devices on the network.
Address Assignment: Devices request IP addresses from the DHCPv6 server, and the server assigns a unique IPv6 address to each device.
Additional Configuration: Beyond IP addresses, DHCPv6 can also provide other configuration information such as DNS server addresses and domain names, similar to DHCP in IPv4 networks.
Managed Address Configuration: This mode indicates that devices should use DHCPv6 for address configuration as well as for other configuration details.
Renewal and Rebinding: DHCPv6 supports lease mechanisms where IP addresses are leased to devices for a specified duration, after which they can be renewed or reassigned.
Stateful DHCPv6 is particularly useful in environments where precise control over IP address assignments and central management of network settings are required.
DHCPv6 Server command Terms:
IPv6 dhcp pool: This command creates a pool and enters the router in DHCPv6 configuration mode.
Address: This command is used to indicate the pool of addresses to be allocated by the server. The lifetime option indicates the valid and preferred lease times in seconds.
IPv6 dhcp server interface: This command binds the DHCPv6 pool to the interface.
The M flag needs to be changed from 0 to 1 using the interface command ipv6 nd managed-config-flag.
DHCPV6 Server stateful Autoconfiguration Example:
We use the diagram below as an example of topology:
R1(config)#ipv6 unicast-routing
R1(config)#ipv6 dhcp pool Stateful_DHCP
R1(config-dhcpv6)#address prefix 2001:df6:adac:1::/64 lifetime infinite infinite
R1(config-dhcpv6)#dns-server AAAA:BBBB:CCCC:DDDD::FFFF
R1(config-dhcpv6)#domain-name orbitCO.com
R1(config-dhcpv6)#exit
R1(config)#interface s0/0/0
R1(config-if)#ipv6 address 2001:df6:adac:1::1/64
R1(config-if)#ipv6 dhcp server Stateful_DHCP
R1(config-if)#ipv6 nd managed-config-flag
How to configure DHCPV6 Client Stateful Autoconfiguration
DHCPv6 Client command Terms:
IPv6 enable interface: This command allows the router to receive a link-local address to send RS messages and participate in DHCPv6.
IPv6 address dhcp interface: This command enables the router as a DHCPv6 client on this interface. This Configuration allows a router to act as a DHCP client.
Example DHCPv6 Client topology configuration:
R2(config)#interface s0/0/0
R2(config-if)#ipv6 enable
R2(config-if)#ipv6 address dhcp
How to verify DHCPv6 Server configuration
Use the show ipv6 dhcp pool command to verify the name of the DHCPv6 pool and its parameters. The number of active clients is 1, which reflects client R2 receiving its IPv6 global unicast address from this server.
R1#show ipv6 dhcp pool
DHCPv6 pool: Stateful_DHCP
Address allocation prefix: 2001:DF6:ADAC:1::/64 valid 4293967297 preferred 4293967297 (1 in use, 0 conflicts)
DNS server: AAAA:BBBB:CCCC:DDDD::FFFF
Domain name: orbitCO.com
Active clients: 1
Use the show ipv6 dhcp binding command, this displays the automatic binding between the link-local address of the client and the address assigned by the server.
R1#show ipv6 dhcp binding
Client: FE80::2
DUID: 000300018C2054EC6F18
Username: unassigned
IA NA: IA ID 0x00070001, T1 43200, T2 69120
Address: 2001:DF6:ADAC:1:2CFA:91CD:C683:D1F5
preferred lifetime INFINITY, valid lifetime INFINITY,
How to verify Stateful DHCPv6 Client configuration
Use the show ipv6 dhcp interface command to view the interfaces that were configured via DHCP. This command also displays the link-local address of the DHCP server.
R2#show ipv6 dhcp interface
Serial0/0/0 is in client mode
Prefix State is IDLE
Address State is OPEN
Renew for address will be sent in 10:32:14
List of known servers:
Reachable via address: FE80::1
DUID: 000300018C2054FF38A0
Preference: 0
Configuration parameters:
IA NA: IA ID 0x00070001, T1 43200, T2 69120
Address: 2001:DF6:ADAC:1:B0A4:64F:CA3F:FA2D/128
preferred lifetime INFINITY, valid lifetime INFINITY
DNS server: AAAA:BBBB:CCCC:DDDD::FFFF
Domain name: orbitCO.com
Information refresh time: 0
Prefix Rapid-Commit: disabled
Address Rapid-Commit: disabled
