Troubleshooting Guide

Table Of Contents
show ipv6 global
5. Verify that the IPv6 based VLAN where the DHCP relay agent is configured is enabled:
show ipv6 interface vlan <1-4059>
6. In a scenario with VRRP and SMLT, configure VRRP IP as the DHCP relay agent.
7. When using the VRRP VRID as the relay agent, make sure the VRRP configurations are
proper.
8. To verify that relay forward and relay receive are working, enable trace for DHCP with IPv6,
and grep trace for relay:
trace level 66 3
trace grep relay
trace screen enable
9. Display the count of DHCP Relay requests and replies to verify the system received requests
and replies:
show ipv6 dhcp-relay counters
IPv6 DHCP Relay server side troubleshooting
Use the following procedure to troubleshoot IPv6 DHCP Relay on the server side.
Procedure
1. Enable the services on the server side, and then create an IP pool.
The IP pool must contain the range of addresses that you want to assign to the clients.
Configure the IP pool with the same network subnet as that of the relay agent.
2. When the configuration is complete, initiate a DHCP request from a client.
3. Check the log file available on the server to verify the reason for packet drop.
4. Capture the packets on the server side using Ethereal.
5. From the server side, use ping to verify that the relay agent address is reachable.
Ensure that a route to the relay is configured.
6. For more configuration aspects, see the Microsoft webpage for troubleshooting and
configuration issues.
Note:
You can receive some log messages that indicate the system cannot forward packets.
However, certain situations are not DHCP failures.
IPv6 DHCP Relay server side troubleshooting
January 2017 Troubleshooting 229
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