This knowledge article explains why an external SNMP walk using a community string on an EX4650 switch displays a numeric OID (for example, jnxChassis.508) instead of the actual chassis model name (jnxChassisEX4650). It also provides the root cause and resolution steps.

Symptoms

When performing an SNMP MIB walk directly on the EX4650 device using the Junos CLI:

show snmp mib walk 1.3.6.1.2.1.47.1.1.1.1

The output correctly displays:

entPhysicalVendorType.1 = jnxChassisEX4650

However, when polling externally from an SNMP server using:

snmpwalk -c <community> -v2c <device> 1.3.6.1.2.1.47.1.1.1.1 -m ALL

The output shows:

ENTITY-MIB::entPhysicalVendorType.1 = OID: JUNIPER-CHASSIS-DEFINES-MIB::jnxChassis.508

Instead of resolving to:

jnxChassisEX4650

The external SNMP query only displays the numeric OID index (for example, jnxChassis.508) and does not translate it to the actual platform name.

Root cause of the issue :

This discrepancy occurs because the external SNMP polling server does not have the complete Juniper Enterprise MIB files installed.

Specifically, the following MIBs are required:

• JUNIPER-CHASSIS-DEFINES-MIB
• JUNIPER-SMI
• JUNIPER-MIB

Without these MIB files, the SNMP tool cannot decode:

• jnxChassis.508 → jnxChassisEX4650
• jnxPic.520 → jnxPicEX465048Y8C

The Junos CLI can display the correct model name because it has built-in knowledge of all Juniper MIB definitions. External SNMP tools rely on locally installed MIB files for symbolic name resolution.

Work Around:

1. Download Juniper Enterprise MIBs

Download the appropriate MIB package (for example, for Junos OS version 22.4R3.25) from the Juniper MIB Explorer:

https://apps.juniper.net/mib-explorer/download?software=Junos%20OS

Navigate to the Juniper Networks software download page and locate the Enterprise MIBs link under the Enterprise-Specific MIBs and Traps section.

2. Install MIB Files on the SNMP Server

Copy the downloaded MIB files to the SNMP server’s MIB directory. For example:

/usr/share/snmp/mibs/

3. Update SNMP Configuration

Edit the

snmp.conf file to ensure that all MIBs are loaded:

mibs +ALL

Restart the SNMP service if required.

4. Re-run the SNMP Walk

After installing the Juniper MIBs, execute:

snmpwalk -c <community> -v2c <device> entPhysicalVendorType

Expected Output:

entPhysicalVendorType.1 = jnxChassisEX4650

5. Validation

Once the MIBs are properly installed and loaded:

• Verify that the chassis model name resolves correctly.
• Confirm that the external SNMP poll using the community string now displays
• jnxChassisEX4650 instead of a numeric OID reference.