DHCP Configuration
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31.5
DHCP Troubleshooting
If the DHCP clients cannot obtain IP addresses and other network parameters, the
following procedures can be followed when DHCP client hardware and cables have been
verified ok.
Verify the DHCP server is running, start the related DHCP server if not running. If the
DHCP clients and servers are not in the same physical network, verify the router
responsible for DHCP packet forwarding has DHCP relay function. If DHCP relay is
not available for the intermediate router, it is recommended to replace the router or
upgrade its software to one that has a DHCP relay function.
In such case, DHCP server should be examined for an address pool that is in the
same segment of the switch VLAN, such a pool should be added if not present, and
(This does not indicate switch cannot assign IP address for different segments, see
solution 2 for details.)
In DHCP service, pools for dynamic IP allocation and manual binding are conflicting,
i.e., if command ―
network-address
‖ and ―
host
‖ are run for a pool, only one of them
will take effect; furthermore, in manual binding, only one IP-MAC binding can be
configured in one pool. If multiple bindings are required, multiple manual pools can be
created and IP-MAC bindings set for each pool. New configuration in the same pool
overwrites the previous configuration.