DHCPv6 Stateless Client

The Dynamic Host Configuration Protocol for IPv6 (DHCPv6) stateless client allows a device to obtain network configuration parameters, such as domain name server (DNS) and domain search list, from a DHCPv6 server without obtaining an IPv6 address from the server. Instead, the IPv6 address is auto-configured using Router Advertisements (RA).

Overview

The DHCPv6 stateless client method is used when the network administrator prefers to use Stateless Address Auto Configuration (SLAAC) for IPv6 address assignment, while still needing to obtain other network configuration parameters from a DHCPv6 server. This method is essential for environments where automatic address configuration is preferred, but additional configuration details are required from the DHCPv6 server.

The process involves a series of messages: Information-Request and Reply. The DHCPv6 message exchange process involves a series of messages between the DHCPv6 client and server to configure network settings. The key messages in this process are:

  • Information-Request: The DHCPv6 client then sends an Information-Request message to the server, asking for specific configuration parameters.
  • Reply: The server responds with a Reply message, providing the requested configuration parameters, such as DNS server addresses and other network settings.
Note: The peer router must send RA messages with the Other (O) flag set to 1, indicating that stateless DHCPv6 is required.

Requirements

This feature has the following hardware or software requirements for feature enablement or usage:

  • DHCPv6 Client is not supported for RUCKUS ICX 7150 devices.
  • A DHCPv6 server must be available on the network to provide IPv6 addresses and configuration parameters.
  • A peer router, which is another router on the same network segment, must be available on the network.

Considerations

This feature has the following considerations pertaining to feature enablement or usage:

  • The DHCPv6 stateless client does not obtain an IPv6 address from the DHCPv6 server. Instead, it gets the IPv6 address from the peer router.
  • The peer router must be configured to support stateless DHCPv6. For more information, refer to Configuring a Peer Device for DHCPv6 Address Auto-configuration.
  • The DHCPv6 client can receive other configuration parameters such as DNS server addresses, domain search lists, and boot file URLs from the DHCPv6 server.
  • The DHCPv6 client must manage the lease times for the assigned configuration parameters, including renewing and rebinding as necessary.
  • The default gateway and prefix length are always obtained via RA messages.
  • Stacking ports, tunnel ports, and loopback ports are not supported.
  • After a stack switchover, the dynamic IP is relearned. Upon reboot or switchover, the DHCPv6 client's lease time is determined by the DHCPv6 server's response. If the server provides the remaining lease time, the client adopts this as its valid lifetime.

Best Practices

Verify that the DHCPv6 client and server are compatible and correctly configured to communicate.

Prerequisites

This feature has the following prerequisites to feature enablement or usage:

  • The peer router must be configured to send Router Advertisement (RA) messages with the Other Configuration Flag (O-flag) set to 1, using the ipv6 nd other-config-flag command. Refer to the RUCKUS FastIron Command Reference for more information.
  • IPv6 must be enabled on the device interface. Refer to the ipv6 enable command in the RUCKUS FastIron Command Reference for more information.
Parent topic: DHCPv6 Client