Cisco Systems Intelligent Gigabit Ethernet Switch Module reports a duplicate IP address - IBM eServer BladeCenter (Type 8677), HS20, JS20, HS40

Resolving The Problem

RETAIN tip: H181587

Because of the interaction with the Management Module, the BladeCenter Cisco Intelligent Gigabit Ethernet Switch Module reports a duplicate IP address. This is caused by the Management Module issuing gratuitous Address Resolution Protocol (ARP) requests over the internal Management Module link to the Cisco Switch Module. When this happens, there is no error. Everything is operating normally.

However, this does cause entries every 10 seconds or so into the syslog in the Cisco Switch Module. Again, this is not a problem. You just need to be aware that duplicate IP addresses are normal operation over interfaces 15 and 16.

The system may be any of the following IBM eServer servers:

• A BladeCenter, type 8677, any model
• A BladeCenter HS40, type 8839, any model
• A BladeCenter HS20, type 8678, any model
• A BladeCenter HS20, type 8832, any model
• A BladeCenter JS20, type 8842, any model

The BladeCenter chassis is configured with the following option:

• Cisco Systems Intelligent Gigabit Ethernet Switch Module, option part number 13N2281

The Management Module is configured with BRET59D and later diagnostics.

The Ethernet Switch completes POST properly.

There is no fix for this problem.

There is no workaround for this problem.

The duplicate IP addresses occur because the Management Module issues gratuitous ARPs on the management interface. The Cisco Switch Module reports this. This is working normally and does not cause any problems in either the Management Module or the Cisco Switch Module. The user needs to ignore these messages in the syslog of the Cisco Switch Module.