Filter
Top Products
3. Troubleshooting Functional Failures in Operation
54
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
Verify if there is a failure occurrence using the show logging command or the show ip
interface command.
No failure
exists.
< IP addresses cannot be assigned to clients.>
A failure exists.
Identify the extent of failure using the
ping 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
the neighboring host and
router is disabled.
Communication between
remote host and router is
disabled.
Verify the status of address
resolution using the show ip arp
command.
Solved
Unresolved
Verify the route information using
the show ip route command.
No route
information
exists.
The route
information
exists.
The next-hop
address is invalid.
Verify the IP network of remote
system. Otherwise, go to
"3.4 Network Interface
Communication Failure."
Analyze the failure on each
routing protocol.
(RIP, BGP, etc.)
Verify the setting
information of filter and
QoS.
Verify the setting
information of DHCP and
BOOTP.