Explanation

SNMP, short for Simple Network Management Protocol, is a set of protocols for managing network devices. SNMP works by sending messages called protocol data units (PDUs) to different parts of a network. SNMP-compliant devices* called "agents" store data about themselves in Management Information Bases (MIBs) and return this data to the SNMP requesters.  
* Lexmark printers are SNMP-compliant devices.

MIB versions

Lexmark network laser printers support version 1 of the printer MIB. The Lexmark1.MIB draws off the RFC1759 and printer 3805 V2 standards. For some queries, the Lexmark printer may reply “unknown”, which is a valid response according to the RFC. 

Examples of MIB implementation

Duplex MIB (OID – Object Identifier):
Using prtMediaPathDescription (OID 1.3.6.1.2.1.43.13.4.1.10) should yield a return value:

•  SNMPv2-SMI::mib-2.43.13.4.1.10.1.2 = STRING: "Duplex Paper Path"

If duplex is not recognized, you would expect to see the return value:   

•  SNMPv2-SMI::mib-2.43.13.4.1.10.1.1 = STRING: "Primary Paper Path"  

Color MIB (OID):

Using prtMarkerSuppliesDescription (OID 1.3.6.1.2.1.43.11.1.1.6) should yield a return value: 

• SNMPv2-SMI::mib-2.43.11.1.1.6.1.1 = STRING: "Cyan Toner"
   
• SNMPv2-SMI::mib-2.43.11.1.1.6.1.2 = STRING: "Magenta Toner"
   
• SNMPv2-SMI::mib-2.43.11.1.1.6.1.3 = STRING: "Yellow Toner"
   
• SNMPv2-SMI::mib-2.43.11.1.1.6.1.4 = STRING: "Black Toner"

If color is not detected, you would expect to see the return value:  

• SNMPv2-SMI::mib-2.43.11.1.1.6.1.1 = STRING: "Black Toner"

Lexmark MIB documentation and support statement

Lexmark provides the MIB information below as a courtesy to network administrators who use SNMP management utilities. Lexmark does not directly support the use of third-party management tools for the administration of our printers and MFPs.
NOTE: We will provide specific information upon request but only if essential to the implementation of our product.

Lexmark MIB file pack

This Lexmark MIB file pack contains:

• Lexmark Private MIB (lexmark1.mib)
• Lexmark Managed Print Services MIB (lexmark-mps-mib.mib)
• Lexmark Root MIB (lexmark-root-mib.mib)
• Lexmark Textual Conventions MIB (lexmark-tc-mib.mib).

NOTE: The referenced MIB files in this package are for use with later (2011 and above) generation products. However, the lexmark1.mib file is viable for both current and older generation products

RFC3805 PrinterV2 MIB

SNMP OID Var2