Troubleshooting

Unusual Network Activity

This can also happen, for example, if the server is first configured to issue IP addresses with an unlimited duration, then is subsequently configured to issue IP addresses that will expire after a limited duration. One solution is to configure “reservations” in the DHCP server for specific IP addresses to be assigned to devices having specific MAC addresses. For more information, refer to the documentation for the DHCP server.

One indication of a duplicate IP address in a DHCP network is this Event Log message:

ip: Invalid ARP source: IP address on IP address

where: both instances of IP address are the same address, indicating the IP address that has been duplicated somewhere on the network.

The Switch Has Been Configured for DHCP/Bootp Operation, But Has

Not Received a DHCP or Bootp Reply. When the switch is first config­ ured for DHCP/Bootp operation, or if it is rebooted with this configuration, it immediately begins sending request packets on the network. If the switch does not receive a reply to its DHCP/Bootp requests, it continues to periodically send request packets, but with decreasing frequency. Thus, if a DHCP or Bootp server is not available or accessible to the switch when DHCP/Bootp is first configured, the switch may not immediately receive the desired configuration. After verifying that the server has become accessible to the switch, reboot the switch to re-start the process.

Prioritization Problems

Ports configured for non-default prioritization (level 1 - 7) are not

performing the specified action. If the ports were placed in a trunk group after being configured for non-default prioritization, the priority setting was automatically reset to zero (the default). Ports in a trunk group operate only at the default priority setting.

CDP Problems

The switch does not appear in the CDP Neighbors table of an adjacent CDP Device. This may be due to any of the following:

■Either the port connecting the switch to the adjacent device is not a member of an untagged VLAN or any Untagged VLAN to which the port belongs does not have an IP address.

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