23.1.4 Notes on Using IPv6 DHCP Servers
The following provides notes on using the IPv6 DHCP server functionality.
- <Structure of this section>
(1) About DUID(DHCP Unique Identifier)
DUIDs are used to identify IPv6 DHCP devices. The Switch generates a DUID the first time an IPv6 DHCP server functionality is used. The generated DUIDs are statically stored in memory inside the Switch. You can check the value of a DUID in the Server DUID section of the list that is displayed when you execute the show ipv6 dhcp server statistics command. When you replace the Switch, the previous DUID is no longer used. If you want to use the previous DUID value, use the set ipv6-dhcp server duid command to re-specify it.
(2) Operation when the Switch is restarted
If either of the events described in the table below occur, some restrictions apply to the Switch. The table describes whether information is preserved when the indicated events occur.
|
Prefix-related information to be retained |
DHCP server functionality restart |
Switch is restarted |
|
|---|---|---|---|
|
Caused by execution of the restart ipv6-dhcpserver command |
Due to a server failure |
||
|
Routing information to the client |
OK |
# |
NG |
|
Prefixes distributed to clients |
OK |
# |
NG |
- Legend
-
OK: Information is preserved.
# : Most information is preserved. Prefixes that are distributed immediately before a restart might not be preserved.
NG: No information is preserved (the information is initialized).
(3) Notes on using the automatic routing facility for a distribution prefix
In situations such as when clients that do not have a function for advertising routing information, the Switch automatically configures routing information. However, the Switch should use the routing information advertised by clients when multiple paths exist or routes are dynamically changed.
The Switch should also use the routing information advertised by clients when other devices are positioned between clients and the Switch because the routing information is not advertised to intermediate devices.
(4) Notes on using IPv6 DHCP servers and IPv6 PIM on the same interfaces
When you run an IPv6 DHCP server on an interface that is enabled with an IPv6 PIM, direct the DHCP control packets from IPv6 DHCP to the global unicast addresses of the Switch, not to the all-servers multicast address (FF05::1:3).