Troubleshoot Dhcp Relay Configuration - Huawei Quidway S3500 Series Operation Manual

Operation Manual - Network Protocol
Quidway S3500 Series Ethernet Switches

4.5 Troubleshoot DHCP Relay Configuration

Fault 1: The user cannot apply for IP address dynamically.
Troubleshoot: Perform the following procedures:
Firstly, use the display dhcp-server groupNo command to check if the IP
address of the corresponding DHCP Server has been configured.
Secondly, use the display vlan and display ip commands to check if the VLAN
and the corresponding interface IP address have been configured.
Then make sure to ping the configured DHCP Server to ensure that the link is
connected.
Ping the IP address of the VLAN interface of the switch to which the DHCP user is
connected from the DHCP Server to make sure that the DHCP Server can
correctly find the route of the network segment the user is on. If the ping execution
fails, check if the default gateway of the DHCP Server has been configured as the
address of the VLAN interface that it locates on.
If there is no problem found in the last two steps, use the display dhcp-server
groupNo command to view what packet has been received. If you only see the
Discover packet and there is no response packet, it means the DHCP Server has
not sent the message to the Ethernet Switch. In this case, you shall check if the
DHCP Server has been configured properly. If the numbers of request and
response packets are normal, enable the debugging dhcp-relay in User view
and then use the terminal debugging command output the debugging
information to the console. In this way, you can view the detailed information of all
DHCP packets on the console during applying for the IP address, thereby
conveniently locating the problem.
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Chapter 4 DHCP Relay Configuration