Dhcp Troubleshooting - Digitalchina Networks DCS-3950 series Manual

DHCPRELAY
DHCPFORWARD
18.3.1.7 debug ip dhcp server
Command：debug ip dhcp server { events|linkage|packets }
no debug ip dhcp server { events|linkage|packets }
Function: Enable DHCP server debug information: the 'no debug ip dhcp server
{ events|linkage|packets }' command disables the debug information for DHCP server.
Default: Debug information is disabled by default.
Command mode: Admin Mode
18.3.1.8 debug ip dhcp client
Command：debug ip dhcp cliet { events|packets }
no debug ip dhcp cliet { events|packets }
Function: Enable DHCP server debug information: the 'no debug ip dhcp cliet
{ events|packets } 'command command disables the debug information for DHCP server.
Default: Debug information is disabled by default.
Command mode: Admin Mode

18.3.2 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 DCS-3950 series 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.
DCS-3950 series Ethernet switch manual
Number of DHCPRELAY packets
Number of DHCPFORWARD packets
317