NEC IP8800/S3600, IP8800/S6600, IP8800/S2400 IP Addresses Cannot Be Assigned Using Dhcp Function

3.Troubleshooting Functional Failures in Operation

3.6.2IP Addresses Cannot Be Assigned Using DHCP Function

(1)DHCP/BOOTP relay communication failure

There are three possible causes for DHCP/BOOTP relay communication failures:

1.Configuration relating to DHCP/BOOTP relay has changed

2.Network configuration has changed

3.DHCP/BOOTP server failures

For 2 above, check for the differences in the network configuration provided before and after the change. Check for any difference disabling communication.

Assuming that client settings (network card setting, cable connection, etc.) have been verified, this section describes the procedure for locating the faulty part and cause in the cases described such as "IP addresses are not assigned from the DHCP/BOOTP server as a result of changing the configuration." and "Although the configuration and network configuration are correct, IP addresses are not assigned and IP communication is disabled" as in above No. 1 and 3.

To locate the faulty part and cause, follow the flow below.

Figure 3-8: Troubleshooting on DHCP/BOOTP Relay

		< IP addresses cannot be assigned to clients.>
	Verify if there is a failure occurrence using the show logging command or the show ip
		interface command.
No failure		A failure exists.

exists.

	See the manuals "Message Log
	Reference" and "3.6.1 Communication Is
	Disabled or Is Disconnected" and perform
Identify the extent of failure using the
	the actions described in [Action]
ping command.
	associated with each log message.

Communication between the neighboring host and router is disabled.

Verify the status of address

resolution using the show ip arp

command.

Unresolved

Communication between remote host and router is disabled.

Solved Verify the route information using the show ip route command.

	The next-hop
No route
information	address is invalid.
exists.

The route

information

exists.

Verify the IP network of remote	Analyze the failure on each
system. Otherwise, go to	routing protocol.
"3.4 Network Interface	(RIP, BGP, etc.)
Communication Failure."

Verify the setting	Verify the setting
information of filter and	information of DHCP and
QoS.	BOOTP.

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