SNMP Data Collection

NetXMS collects metrics from network devices and systems using SNMP (Simple Network Management Protocol). SNMP data collection supports versions 1, 2c, and 3, and provides tools for MIB browsing, OID discovery, and SNMP table collection.

For SNMP protocol configuration (versions, credentials, proxy), see SNMP Configuration. For MIB file management and the MIB Explorer, see MIB Management. For OID format reference, counter handling, and troubleshooting, see SNMP Data Collection Reference. For an explanation of SNMP table OID structure, see Understanding SNMP Table Structure.

Creating SNMP DCIs

Using MIB Explorer

The simplest way to create an SNMP DCI is via the MIB Explorer:

  1. Right-click the node and select MIB Explorer

  2. Navigate the MIB tree or search for the desired OID

  3. Select the OID and click Walk to see current values

  4. Right-click the desired value in the walk results and select Create data collection item…​

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

To create a table DCI directly from the MIB tree, right-click the table OID and select Create SNMP table DCI…​.

Manual DCI Creation

  1. Open the node’s Data Collection view

  2. Click New parameter…​

  3. Set Origin to SNMP

  4. Enter the OID in the Metric field in numeric dotted-decimal format (symbolic names are not accepted), or use the selection button next to the field to pick the OID from the MIB tree

  5. Set the appropriate data type

  6. Configure polling interval and retention time

SNMP Tables

For an explanation of how SNMP table OIDs are structured, see Understanding SNMP Table Structure.

Creating a Table DCI

To create a table DCI:

  1. Open the node’s Data Collection view

  2. Click New table…​

  3. Set Origin to SNMP

  4. In the Metric field, enter a table column OID (XXXYYY format)

    Use any column that returns non-empty results in MIB Explorer. For example: 1.3.6.1.2.1.2.2.1.1 (ifIndex column). The walk on this OID discovers all row instances.

  5. Go to the Table Columns property page to define which columns to collect.

    You can add columns manually by specifying the full column OID for each, or use the Query…​ button to auto-discover columns.

Using the Query Button

The Query…​ button on the Table Columns page automatically discovers all columns in the table:

  1. It strips the column part from the metric OID to get the table base OID

  2. Performs an SNMP walk on the table base

  3. Creates column definitions for each discovered column

  4. Maps SNMP data types (INTEGER, OCTET STRING, Counter32, etc.) to NetXMS data types

If columns already exist, the query will replace them. A confirmation dialog appears before proceeding.

Configuring Instance Columns

To configure an instance column, edit the column definition in the Table Columns page and enable the This column is instance (key) column checkbox.

See Instance Columns for why this is important.

Hexadecimal String Display

Some SNMP columns return octet strings that contain binary data (e.g., MAC addresses). These values may display as unreadable characters. To fix this, edit the column definition and enable Convert SNMP value to hexadecimal string.

Table DCI with Instance Discovery

For single-value DCIs where you want one DCI per table row, use instance discovery with one of the SNMP walk methods:

  1. Create a DCI with the column OID and {instance} suffix placeholder

    • Example metric: .1.3.6.1.2.1.2.2.1.10.{instance} (ifInOctets)

  2. On the Instance Discovery property page, select the discovery method:

    • SNMP Walk - Values — each value returned by the walk becomes an instance (e.g., walking .1.3.6.1.2.1.2.2.1.1 (ifIndex) yields the interface indexes)

    • SNMP Walk - OIDs — the OID suffix below the base OID becomes the instance, and the returned value becomes the instance name (e.g., walking .1.3.6.1.2.1.2.2.1.2 (ifDescr) yields interface indexes as instances named after the interface descriptions)

  3. Set Base SNMP OID to the column to walk

NetXMS walks the configured column to discover all rows, then creates a DCI for each row with the {instance} placeholder replaced by the discovered instance. Instance names can also be modified in the instance discovery filter script.

Bulk Operations

SNMP Walk for DCI Creation

You can walk an OID subtree and create DCIs for all discovered OIDs:

  1. Open MIB Explorer on the target node

  2. Walk the desired subtree

  3. Select multiple OIDs from the results

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

Copying SNMP DCIs Between Nodes

SNMP DCIs can be copied between nodes or to templates:

  1. Select DCIs in the Data Collection view

  2. Right-click and select Move or Copy, then Copy to other object(s)…​ or Move to other object(s)…​

  3. Select the target node or template

When copying to a template, the DCIs are automatically deployed to all nodes bound to the template.