CISCO-L2NAT-MIB

MIB Reference — IPNetwork Monitor · Updated September 14, 2026

All MIBsCISCO-L2NAT-MIB

Organization: Cisco Systems, Inc.

Last Updated: 2013-04-16

Category: Cisco Devices, VLAN and Bridging, VPN and Security

Description: Manages Layer 2 Network Address Translation for address rewriting at the Ethernet frame level.

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What Is CISCO-L2NAT-MIB?

CISCO-L2NAT-MIB is a Cisco vendor-specific MIB that manages Layer 2 Network Address Translation, address rewriting performed on switched Ethernet frames rather than routed IP packets, primarily targeting Cisco Industrial Ethernet switches. It exposes global counters (cl2natTotalInstances, cl2natTotalMatched, cl2natTotalUnmatched, cl2natTotalFixups, cl2natTotalPacketTranslated) alongside cl2natInstConfigInstanceTable, which defines named L2NAT instances with cl2natInstConfigPermitIn/PermitOut BITS objects (controlling unmatched/IGMP/multicast traffic handling) and cl2natInstConfigFixup BITS covering protocol-aware payload rewriting for arp, icmp, profinet, cip, and snmp. Per its own description the module also includes companion interface-config and interface-statistics table pairs for applying an instance to a specific interface/VLAN combination and tracking its per-interface hit counts. This data is useful for confirming NAT translation rules are actually matching expected traffic, a growing cl2natTotalUnmatched relative to cl2natTotalMatched suggests misconfigured or incomplete translation entries, which matters in industrial-automation networks where duplicate IP address ranges are common across cells. It depends on INET-ADDRESS-MIB and CISCO-TC for address-typed and masked objects used in translation entries, and it is deployed on Cisco Industrial Ethernet switches performing L2 NAT between automation cells, as documented in this CISCO-L2NAT-MIB MIB Browser reference to its instance and statistics tables.

IPNetwork Monitor allows you to monitor SNMP objects defined in CISCO-L2NAT-MIB. Use the built-in SNMP Monitoring Browser to explore available variables, view their current values and descriptions, and select the objects you want to monitor. You can then create SNMP monitors, configure thresholds, and receive alerts when monitored values change.

Supported Devices

  • Cisco Industrial Ethernet switches (IE-series) performing Layer 2 NAT

Monitoring Examples

An operator polls cl2natTotalMatched against cl2natTotalUnmatched and reviews cl2natInstConfigPermitIn/PermitOut for a given instance in cl2natInstConfigInstanceTable; a sudden spike in cl2natTotalUnmatched after a device swap would indicate the new device's IP address isn't covered by any configured translation entry in that instance.

What Can Be Monitored

  • global instance count and total matched/unmatched packet counters
  • fixup (payload rewrite) packet counters
  • per-instance permit-in/permit-out and fixup protocol bits
  • translation entry configuration count
  • per-interface/VLAN translation statistics
Imported Objects

From CISCO-SMI

ciscoMgmtOBJECT-IDENTITY

From CISCO-TC

CiscoInetAddressMask

From INET-ADDRESS-MIB

InetAddress
InetAddressType

From SNMP-FRAMEWORK-MIB

SnmpAdminString

From SNMPv2-CONF

MODULE-COMPLIANCE
OBJECT-GROUP

From SNMPv2-SMI

Counter32
Counter64
Integer32
MODULE-IDENTITY
OBJECT-TYPE
Unsigned32

From SNMPv2-TC

RowStatus
StorageType
OIDs

RFC description

Manages Layer 2 Network Address Translation for Cisco Industrial Ethernet switches.

Start monitoring Cisco Industrial Ethernet switches (Layer 2 NAT) with a free 30-day trial of IPNetwork Monitor. Import MIBs, browse SNMP OIDs, create custom SNMP monitors, configure alerts, and monitor any SNMP-enabled network device from a single console.

Download CISCO-L2NAT-MIB