Configuration Considerations for DHCPv6 Servers
The following configuration considerations apply to DHCPv6 servers.
- For the DHCPv6 server to be enabled, you must upgrade to FastIron release 08.0.90 or later using the Unified FastIron Image (UFI). Refer to the Software Upgrade and Downgrade chapter in the RUCKUS FastIron Software Upgrade Guide for more information.
- The DHCPv6 server is not supported for non-default VRFs.
- The ICX DHCPv6 server does not assign IPv6 addresses via DHCPv6 relay.
- IPv6 unicast routing must be enabled.
- For stateless DHCPv6 servers, IPv6 addresses are assigned to the clients through auto-configuration. The DHCPv6 server is used only to assign information such as domain-names, multiple DNS servers, and other supported DHCPv6 options. One ICX interface should be configured with an IPV6 address that falls in the subnet range configured for the DHCPv6 server.
- The DHCPv6 lease expiry is calculated as current-time + valid-lifetime. This value must not exceed 2,147,483,647 seconds due to a 32-bit signed integer limit. If exceeded, the configuration is rejected to prevent lease database corruption.
- Neighbor discovery protocol (NDP) should be configured for stateless DHCPv6 servers.
- A FastIron device configured as a DHCPv6 server can support up to 500 DHCP clients.
- Up to 100 DHCPv6 subnets can be configured for the DHCPv6 server.
- When the rapid commit option is configured on the server, only Solicit and Reply packets are sent between the client and the server instead of Solicit, Advertise, Request and Reply. For the rapid commit mode to work, the client should also have the rapid commit option enabled.
- Whenever a configuration change is made with respect to the DHCPv6 server, the configuration change is written to the dhcpd.conf file in Linux within 30 seconds. When this occurs, the dhcpd process restarts.