Ip Addresses Cannot Be Assigned Using Dhcp Function - NEC IP8800/S2400 Series Troubleshooting Manual

3.
Troubleshooting Functional Failures in Operation
3.6.2

IP 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
Identify the extent of failure using the
Communication between
the neighboring host and
router is disabled.
Verify the status of address
resolution using the show ip arp
command.
Unresolved
Verify the IP network of remote
system. Otherwise, go to
"3.4 Network Interface
Communication
54
< IP addresses cannot be assigned to clients.>
Verify if there is a failure occurrence using the show logging command or the show ip
No failure
exists.
ping command.
Solved
No route
information
exists.
Failure."
Verify the setting
information of filter and
interface command.
See the manuals "Message Log
Reference" and "3.6.1 Communication Is
Disabled or Is Disconnected" and perform
the actions described in [Action]
associated with each log message.
Communication between
remote host and router is
disabled.
Verify the route information using
the show ip route command.
The next-hop
address is invalid.
Analyze the failure on each
routing protocol.
(RIP, BGP, etc.)
Verify the setting
information of DHCP and
QoS.
A failure exists.
The route
information
exists.
BOOTP.