MIB Management

MIB (Management Information Base) files define the structure and meaning of SNMP objects exposed by devices. NetXMS includes a built-in MIB compiler and browser that allows you to load vendor-specific MIBs and navigate the OID tree with human-readable names and descriptions.

MIB Concepts

Each SNMP object is identified by a numeric OID (Object Identifier), such as .1.3.6.1.2.1.1.3.0. MIB files provide:

  • Human-readable names for OIDs (e.g., sysUpTime)

  • Data type information (integer, string, counter, gauge, etc.)

  • Description text explaining what the object represents

  • Table structure definitions with index and column information

NetXMS ships with standard MIBs (SNMPv2-MIB, IF-MIB, HOST-RESOURCES-MIB, etc.) pre-loaded. Vendor-specific MIBs must be uploaded manually.

Loading MIB Files

Via Management Client

  1. In the management client, go to Configuration > SNMP MIB files

  2. Upload the MIB file — this only stores the file in the server’s user MIB directory

  3. Select Compile to run the MIB compiler and rebuild the compiled MIB file

  4. After compilation, new OIDs from the MIB become available in the MIB Explorer

Server MIB Directories

MIB files are stored in two directories on the server:

  • <sharedir>/mibs — standard MIB files shipped with NetXMS

  • <datadir>/mibs — user-provided MIB files (this is where uploaded files are stored)

The server does not compile MIB files at startup — it loads the prebuilt compiled MIB file, netxms.cmib. Compilation is performed by the nxmibc compiler at installation time or on demand (via the Compile action in the SNMP MIB files view, or by running nxmibc manually).

MIB Dependencies

MIB files often import definitions from other MIBs. If an imported module is missing, the MIB compiler reports the missing module name.

The compiler processes all files from both MIB directories in a single run, so upload order does not matter — just make sure all dependencies are present. Standard IETF and IANA MIBs are shipped with the server and do not need to be uploaded.

MIB Explorer

The MIB Explorer provides interactive access to the SNMP OID tree on a specific device.

Opening MIB Explorer

Right-click a node and select MIB Explorer to open it. The explorer is also available as the MIB explorer tool in the Tools perspective. The explorer shows:

  • A tree view of the MIB hierarchy on the left

  • OID details (name, numeric OID, type, description) on the right

  • SNMP walk results with live values from the device

Navigating the MIB Tree

The MIB tree is organized hierarchically:

iso(1)
  └─ org(3)
      └─ dod(6)
          └─ internet(1)
              ├─ mgmt(2)
              │   └─ mib-2(1)
              │       ├─ system(1)
              │       ├─ interfaces(2)
              │       └─ ...
              └─ private(4)
                  └─ enterprises(1)
                      ├─ cisco(9)
                      ├─ hp(11)
                      └─ ...

Click any node in the tree to see its details. Vendor MIBs appear under the enterprises branch.

MIB Walk

Use MIB Walk to discover all available OIDs on a device:

  1. In the MIB Explorer, enter a starting OID (e.g., .1.3.6.1.2.1 for standard MIB-II objects)

  2. Click Walk

  3. The results show all OIDs under that subtree with their current values and MIB descriptions

This is useful for:

  • Discovering what a device exposes before creating DCIs

  • Verifying SNMP connectivity and credentials

  • Troubleshooting by checking real-time values

  • Finding the correct OIDs for monitoring

Creating DCIs from MIB Explorer

You can create DCIs directly from walk results:

  1. Walk the desired OID subtree

  2. Select one or more OIDs from the results

  3. Right-click and select Create data collection item…​

  4. Configure the description, polling interval, retention time, and delta calculation

See SNMP Data Collection for details on SNMP DCI configuration.

Server MIB Compilation

The MIB compiler (nxmibc) converts all MIB source files from both MIB directories into a single binary file, netxms.cmib, for fast access. Management clients download the compiled file from the server.

If a MIB file fails to compile:

  • Check for syntax errors in the MIB file (some vendor MIBs have non-standard syntax)

  • Ensure all imported modules are available in one of the MIB directories

  • Review the compilation output for detailed error messages

By default, nxmibc stops at the first error. The -a option makes it continue after errors, so a single broken MIB file does not prevent the remaining files from being compiled. The server-triggered compilation (the Compile action) runs the compiler with -a; when running nxmibc manually, add -a to get the same behavior.

OID Formats

Configuration (DCIs, trap mappings) always uses numeric dotted-decimal OIDs, e.g. .1.3.6.1.2.1.1.3.0. Loaded MIBs are used for display and browsing: the MIB browser shows the object name (e.g., sysUpTime) together with its full numeric OID and inserts the numeric OID when an object is selected.