CISCO Devices Not Showing the Correct Value for the Serial_Number Attribute

Products

• DX NetOps

Issue/Introduction

We have noticed that some of the Cisco Catalyst 9300 devices are showing incorrect values for the Serial_Number/0x10030 attribute.

Environment

The Serial_Number attribute reads the value of the attribute pointed to by the DeviceSerialAttr attribute. By default, for most cisco
  devices the DeviceSerialAttr/0x3d0063 attribute. In this case DeviceSerialAttr points to the handle 0x210b5d
   which is the chassisId attribute (1.3.6.1.4.1.9.3.6.3.0)

0x3d0063    DeviceSerialAttr    0x210b5d
0x210b5d    chassisId    ###########
0x10030      Serial_Number    ###########

Cause

Some devices had 'snmp-server chassis-id' being set in their configuration. The value set overrides the chassisid value and was the cause of
   the incorrect values for the Serial_Number.


chassisId OBJECT-TYPE
 SYNTAX DisplayString (0 .. 255)
 ACCESS read-write
 STATUS deprecated
 
 DESCRIPTION
 "Unique ID string. Defaults to chassis serial
                           number if available, otherwise empty. Can
                           also be set with 'snmp-server chassis-id'."
  ::= { chassis 3 }
 
-- 1.3.6.1.4.1.9.3.6.3

Resolution

The devices in question would need to have 'snmp-server chassis-id' unset in the configuration.