NEC IP8800/S2400 Series Troubleshooting Manual page 137

Check the number of remaining prefixes that can be distributed from the IPv6DHCP server using the show ipv6 dhcp
server statistics command. For the instructions, see "Configuration Settings." If the distributable number of prefixes
is 0, increase the number of prefixes to be distributed. The prefixes can be distributed up to 1024.
(c) Procedure to check configuration
1. Confirm that IPv6DHCP server functions is enabled.
Execute configuration command show service to confirm that the "IPv6 DHCP" server is enabled. If the
underlined part in the following results is not displayed, the "IPv6 DHCP" server is enabled.
[Execution results]
(config)# show service
no service ipv6 dhcp
!
(config)#
2. Checking "ipv6 dhcp server" setting.
Execute configuration command show to confirm that the "ipv6 dhcp server" setting presents. If not configured, add
the configuration. If the setting presents, confirm that the specified interface supports the network on which clients
are connected.
[Execution results]
(config)# show
interface vlan 10
ipv6 address 3ffe:1:2:: linklocal
ipv6 enable
ipv6 dhcp server Tokyo preference 100
!
(config)#
3. Check the setting of ipv6 dhcp pool/ipv6 local pool/prefix-delegation/prefix-delegation pool.
Execute configuration command show ipv6 dhcp to confirm that the prefix distribution from the "IPv6DHCP"
server is configured. If not configured, add the configuration. If this feature is configured, confirm that the value
specified in "prefix-delegation/ipv6 local pool," which determine the prefix to be distributed, and presence/absence
of "duid" configuration, which determine the target clients for the distribution, and the client DUID value defined in
"duid" are correct.
[Execution results]
(config)# show ipv6 dhcp
ipv6 dhcp pool Tokyo
prefix-delegation 3ffe:1:2::/48 00:03:00:01:11:22:33:44:55
!
(config)#
(d) Duplicate acquisition by the client
1. Checking binding information
Execute the show ipv6 dhcp binding command with "detail" parameter specified to confirm that only one
prefix is distributed for each DUID. An example is as follows.
[Execution results]
> show ipv6 dhcp binding detail
Total: 2 prefixes
<Prefix>
<DUID>
3ffe:1234:5678::/48
00:01:00:01:55:55:55:55:00:11:22:33:44:55
3ffe:aaaa:1234::/48
00:01:00:01:55:55:55:55:00:11:22:33:44:55
>
As displayed in the underlined portion, if the same DUID appears two or more times, it may be a client that is
improperly acquiring prefix information. Check each client and confirm the distributed prefixes value.
2. Matching distributed prefixes and clients
If no client is found that is acquiring duplicated prefixes as the results of the show ipv6 dhcp binding
<Lease expiration>
05/04/01 11:29:00
05/04/01 11:29:00
3.
Troubleshooting Functional Failures in Operation
<Type>
Automatic
Automatic
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