Troubleshooting guide

3. Troubleshooting Functional Failures During Operation
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(config)#
(d) Duplicate assignment to a client
1. Checking the binding information
Use the
show ipv6 dhcp binding command with the detail parameter to check whether
multiple prefixes have been distributed to a single DUID. The following shows an example.
[Execution result]
> show ipv6 dhcp binding detail
Total: 2 prefixes
<Prefix> <Lease expiration> <Type>
<DUID>
3ffe:1234:5678::/48 05/04/01 11:29:00 Automatic
00:01:00:01:55:55:55:55:00:11:22:33:44:55
3ffe:aaaa:1234::/48 05/04/01 11:29:00 Automatic
00:01:00:01:55:55:55:55:00:11:22:33:44:55
>
If the same DUIDs are displayed multiple times as shown in the underlined lines, the relevant
client might have incorrectly received prefix information. Check the prefix value distributed
to each client.
2. Establishing correspondences between the distributed prefixes and clients
If you cannot find a client with duplicate prefixes in the result of the
show ipv6 dhcp binding
detail command, establish correspondences between the displayed DUIDs and client
devices. To establish correspondences between them, check the binding information to
compare the distributed prefix values and the information of the prefixes distributed to the
client devices.
(e) Checking the client setting status
To check the setting status of the clients, follow the documentation provided with each client.
(f) Procedure for recovering from duplicate distribution
If you have confirmed that the IPv6 DHCP server on the Switch distributed multiple prefixes to a
client, find currently unused prefixes, based on correspondences between the displayed DUIDs and
clients. Use the
clear ipv6 dhcp binding <unused prefix> command to delete the binding
information of each currently unused prefix.
[Execution result]
> show ipv6 dhcp binding detail
Total: 2 prefixes
<Prefix> <Lease expiration> <Type>
<DUID>
3ffe:1234:5678::/
48 05/04/01 11:29:00 Automatic
00:01:00:01:55:55:55:55:00:11:22:33:44:55
3ffe:aaaa:1234::/48 05/04/01 11:29:00 Automatic
00:01:00:01:55:55:55:55:00:11:22:33:44:55
> clear ipv6 dhcp binding 3ffe:1234:5678::/48
> show ipv6 dhcp binding detail
<Prefix> <Lease expiration> <Type>
<DUID>
3ffe:aaaa:1234::/48 05/04/01 11:29:00 Automatic
00:01:00:01:55:55:55:55:00:11:22:33:44:55
>
(2) Communication to a prefix distribution target is not possible
The automatic routing information setting functionality can be used for distributing prefixes from
the DHCP server on the Switch to prefix assignment targets. If the routing information cannot be
set with the functionality, there are two probable causes.