The page below is from the manual of PRTG, our quick-to-install and easy-to-use network monitoring software

Try PRTG now and see how it can make your job easier.
 

Free Trial Download
You will be up and running in 2 minutes
Learn More
Screenshots, Features, Videos


Aurelio, System Admin at Paessler AG

The SNMP Library sensor monitors a device using Simple Network Management Protocol (SNMP) in combination with a compiled Management Information Base (MIB) library file. This provides custom monitoring beyond the standard SNMP sensors of PRTG. The content of the Management Information Base (MIB) file will determine which data types are available for monitoring. A selection drawn from the OIDs in the MIB is offered when creating the sensor.

To custom monitor SNMP capable devices, download the manufacturer's MIB files for the respective device, convert the Management Information Base (MIB) file to the Paessler oidlib format, and import it into PRTG. To make setting up your monitoring  as convenient as possible, PRTG comes with pre-compiled oidlib library files that already contain the Object Identifier (OID) of SNMP counters for the most common devices in a network. See section More for details.

SNMP Library SensorSNMP Library Sensor

Click here to enlarge: http://media.paessler.com/prtg-screenshots/snmp_library.png

Remarks

Add Sensor

Manually add a new sensor to an SNMP device. From the Add Sensor dialog, select SNMP Library sensor. PRTG will show a list of oidlib files available on the system. This contains all library files stored at the \snmplibs folder of your PRTG installation directory—both the ones delivered with PRTG and your own files. For details about directory paths, please see section Data Storage .

List of SNMP Library FilesList of SNMP Library Files

The file names on the list indicate the likely purpose. Select a name that appears appropriate for your device (for example, choose an MIB file that you imported before) and confirm via OK . Often, the Paessler common oid library.oidlib is a good start. If the file does not fit to your device, this will result in the error message the scan for available monitoring items has failed on this device: No such object (SNMP error # 222) . If you see this message, click Cancel and try adding the sensor with another file. If counters were found for your device, you will see the sensor's settings.

Default OIDLIB Files Overview

The following files are included in PRTG and allow the extension of your SNMP monitoring to many devices. Please be aware that not all devices and/or parameters may be supported by the libraries.

  • APC UPS.oidlib
    Can be used to monitor uninterruptible power supplies (UPS) from APC American Power Conversion Corp.
  • APCSensorstationlib.oidlib
    Can be used to monitor alarm status, communication status, humidity, and temperature as shown by an APC sensor station.
  • Basic Linux Library (UCD-SNMP-MIB).oidlib
    Can be used to monitor basic system parameters on Linux systems, such as memory, disk and swap, CPU, etc.
  • cisco-interfaces.oidlib
    Can be used to monitor Cisco specific parameters, for example, the number of present network interfaces on a system, several states of an interface (admin, oper, speed, type, errors, discards, etc.), and more.
  • cisco-queue.oidlib
    Can be used to monitor queues on a Cisco interface, for example, queue depth and its maximum, discarded messages from the queue, the number of the queue within the queue set, etc.
  • Dell Storage Management.oidlib
    Can be used to monitor Dell storage devices. Possible parameters include disk arrays, battery and power supply, fan and temperature, virtual disk, etc.
  • Dell Systems Management Instrumentation.oidlib
    Can be used to monitor the hardware of Dell systems. Possible parameters include ACPower and battery, alerts, base board, Bios, BMC, chassis, COO, cooling, event log, firmware, IDE, keyboard, memory, port, network, processor, SCSI, system, temperature, USB, UUID, etc.
  • HP LaserJet Status.oidlib
    Can be used to monitor toner, paper, and jam status of an HP LaserJet printer.
  • Linux SNMP (AX BGP DisMan EtherLike Host).oidlib
    Can be used to monitor different aspects of Linux systems.
    icon-i-round This file may detect a very large number of interfaces. It may take a few seconds until the selection table is shown.
  • Linux SNMP (Framework Proxy Noti v2).oidlib
    Can be used to monitor different aspects of Linux systems.
    icon-i-round This file may detect a very large number of interfaces. It may take a few seconds until the selection table is shown.
  • Linux SNMP (IP Net SNMP Noti OSPF RMON SMUX).oidlib
    Can be used to monitor different aspects of Linux systems.
    icon-i-round This file may detect a very large number of interfaces. It may take a few seconds until the selection table is shown.
  • Linux SNMP (Source TCP UCD UDP).oidlib
    Can be used to monitor different aspects of Linux systems.
    icon-i-round This file may detect a very large number of interfaces. It may take a few seconds until the selection table is shown.
  • Paessler Common OID Library.oidlib
    Can be used to monitor many common hardware devices. It is used for several sensors and is encrypted.
  • SNMP Informant std.oidlib
    Can be used to monitor logical disks, processor, memory, and network interface on Windows systems.

Import MIB Files

Additionally you can create your own oidlib files by importing your device manufacturers' MIB files with the free tool Paessler MIB Importer . Simply convert your mib files and save the resulting oidlib files to the \snmplibs subfolder of your PRTG program directory. For details about directory paths, please see Data Storage . For more information and download of MIB Importer , please see the link in the More section below.

icon-i-round icon-tools If your imported oidlib file contains lookups (you can see this in section Lookup in the MIB Importer), you can define your own sensor states for returning values. Add an SNMP Library sensor using this oidlib. PRTG then creates a lookup definition file using the lookupname of the chosen library as id parameter. Override this lookup definition with your own custom lookup as described in section Define Lookups—Customizing Lookups.

SNMP Library Sensor—Add Sensor Settings

The following settings for this sensor differ in the Add Sensor dialog in comparison to the sensor's settings page.

SNMP Library Specific

Library

This shows the path to the oidlib file selected before. This setting is shown for your information only and cannot be changed here.

Library-OIDs

Select the aspects of the device you want to monitor. A list specific to your setup is shown. It contains all counters found in the chosen library that match your device. Select one or more items by adding a check mark in front of the respective line. You can also select and deselect all items by using the check box in the table head. For each selection, PRTG will create one sensor when you click the Continue button.

Sensor Settings

On the details page of a sensor, click the Settings tab to change its settings.

icon-i-round Usually, a sensor connects to the IP Address or DNS Name of the parent device where you created this sensor. See the Device Settings for details. For some sensor types, you can define the monitoring target explicitly in the sensor settings. Please see below for details on available settings.

Basic Sensor Settings

Sensor Name

Enter a meaningful name to identify the sensor. By default, PRTG shows this name in the device tree, as well as in alarms, logs, notifications, reports, maps, libraries, and tickets.

Parent Tags

Shows Tags that this sensor inherits from its parent device, group, and probe. This setting is shown for your information only and cannot be changed here.

Tags

Enter one or more Tags , separated by spaces or commas. You can use tags to group sensors and use tag–filtered views later on. Tags are not case sensitive. We recommend that you use the default value.

You can add additional tags to the sensor if you like. Other tags are automatically inherited from objects further up in the device tree. These are visible above as Parent Tags .

Priority

Select a priority for the sensor. This setting determines where the sensor is placed in sensor lists. Top priority is at the top of a list. Choose from one star (low priority) to five stars (top priority).

SNMP Library Specific

Selected Interface

Shows the counter that this sensor monitors. Once a sensor is created, you cannot change this value. It is shown for reference purposes only. If you need to change this, please add the sensor anew.

Unit String

Enter a string that represents the unit of the returned values. This is for display purposes for the sensor data only. Please enter a string.

Multiplication

Enter the multiplier if you want to multiply the received data by a certain value. Please enter an integer value.

Division

Enter the divisor if you want to divide the received data by a certain value. Please enter an integer value.

If Value Changes

Define what this sensor will do when the sensor value changes. You can choose between:

  • Ignore changes (default) : The sensor takes no action on change.
  • Trigger 'change' notification : The sensor sends an internal message indicating that its value has changed. In combination with a Change Trigger , you can use this mechanism to trigger a notification whenever the sensor value changes.

Sensor Display

Primary Channel

Select a channel from the list to define it as the primary channel. In the device tree, the last value of the primary channel will always be displayed below the sensor's name. The available options depend on what channels are available for this sensor.

icon-i-round You can set another primary channel later by clicking the pin symbol of a channel in the sensor's Overview tab.

Graph Type

Define how different channels will be shown for this sensor.

  • Show channels independently (default) : Show an own graph for each channel.
  • Stack channels on top of each other : Stack channels on top of each other to create a multi-channel graph. This will generate an easy-to-read graph that visualizes the different components of your total traffic.
    icon-i-round This option cannot be used in combination with manual Vertical Axis Scaling (available in the Sensor Channels Settings settings).

Stack Unit

This setting is only available if stacked graphs are selected above. Choose a unit from the list. All channels with this unit will be stacked on top of each other. By default, you cannot exclude single channels from stacking if they use the selected unit. However, there is an advanced procedure to do so.

Inherited Settings

By default, all following settings are inherited from objects higher in the hierarchy and should be changed there, if necessary. Often, best practice is to change them centrally in the Root group's settings. To change a setting only for this object, disable inheritance by clicking the check mark in front of the corresponding setting name. You will then see the options described below.

Scanning Interval

Scanning Interval

Select a scanning interval (seconds, minutes, or hours) from the list. The scanning interval determines the time the sensor waits between two scans. You can change the available intervals in the system administration on PRTG installations.

If a Sensor Query Fails

Define the number of scanning intervals that a sensor has time reach and check a device again in case a sensor query fails. The sensor can try to re-reach and check a device several times, depending on the option you select here, before it will be set to a Down status. This helps you avoid false alarms if the monitored device has only temporary issues. For previous scanning intervals with failed requests, the sensor will show a Warning status. Choose between:

  • Set sensor to "down" immediately : The sensor will show an error immediately after the first failed request.
  • Set sensor to "warning" for 1 interval, then set to "down" (recommended) : After the first failed request, the sensor will show a yellow warning status. If the following request also fails, the sensor will show an error.
  • Set sensor to "warning" for 2 intervals, then set to "down" : Show an error status only after three continuously failed requests.
  • Set sensor to "warning" for 3 intervals, then set to "down" : Show an error status only after four continuously failed requests.
  • Set sensor to "warning" for 4 intervals, then set to "down" : Show an error status only after five continuously failed requests.
  • Set sensor to "warning" for 5 intervals, then set to "down" : Show an error status only after six continuously failed requests.

icon-i-round Sensors that monitor via Windows Management Instrumentation (WMI) always wait at least one scanning interval until they show an error. It is not possible to set a WMI sensor to "down" immediately, so the first option will not apply to these sensor types. All other options can apply.

icon-i-round If a sensor has defined error limits for channels, it will always show a Down status immediately, so no "wait" option will apply.

icon-i-round If a channel uses lookup values, it will always show a Down status immediately, so no "wait" options will apply.

Schedules, Dependencies, and Maintenance Window

icon-i-round Inheritance for schedules, dependencies, and maintenance windows cannot be interrupted. The corresponding settings from the parent objects will always be active. However, you can define additional settings here. They will be active at the same time as the parent objects' settings.

Schedule

Select a schedule from the list. Schedules can be used to monitor for a certain time span (days, hours) every week. With the period list option it is also possible to pause monitoring for a specific time span. You can create new schedules and edit existing ones in the account settings.

icon-i-round Schedules are generally inherited. New schedules will be added to existing ones, so all schedules are active at the same time.

Maintenance Window

Specify if you want to set up a one-time maintenance window. During a "maintenance window" period, this object and all child objects will not be monitored. They will be in a paused state instead. Choose between:

  • Not set (monitor continuously) : No maintenance window will be set and monitoring will always be active.
  • Set up a one-time maintenance window : Pause monitoring within a maintenance window. You can define a time span for a monitoring pause below and change it even for a currently running maintenance window.

icon-i-round To terminate a current maintenance window before the defined end date, change the time entry in Maintenance Ends field to a date in the past.

Maintenance Begins

This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the start date and time of the maintenance window.

Maintenance Ends

This field is only visible if you enabled the maintenance window above. Use the date time picker to enter the end date and time of the maintenance window.

Dependency Type

Define a dependency type. Dependencies can be used to pause monitoring for an object depending on the status of another. You can choose between:

  • Use parent : Pause the current sensor if the device, where it is created on, is in Down status, or is paused by another dependency.
  • Select object : Pause the current sensor if the device, where it is created on, is in Down status, or is paused by another dependency. Additionally, pause the current sensor if a specific other object in the device tree is in Down status, or is paused by another dependency. Select below.
  • Master object for parent : Make this sensor the master object for its parent device. The sensor will influence the behavior of the device, where it is created on: If the sensor is in Down status, the device will be paused. For example, it is a good idea to make a Ping sensor the master object for its parent device to pause monitoring for all other sensors on the device in case the device cannot even be pinged. Additionally, the sensor will be paused if the parent group of its parent device is in Down status, or if it is paused by another dependency.

icon-i-round Testing your dependencies is easy! Simply choose Simulate Error Status from the context menu of an object that other objects depend on. A few seconds later all dependent objects should be paused. You can check all dependencies in your PRTG installation by selecting Devices | Dependencies from the main menu bar.

Dependency

This field is only visible if the Select object option is enabled above. Click on the reading-glasses and use the object selector to choose an object on which the current sensor will depend.

Dependency Delay (Sec.)

Define a time span in seconds for a dependency delay. After the master object for this dependency goes back to Up status, PRTG will start monitoring the depending objects after this extra delayed. This can help to avoid false alarms, for example, after a server restart, by giving systems more time for all services to start up. Please enter an integer value.

icon-i-round-red This setting is not available if you choose this sensor to Use parent or to be the Master object for parent . In this case, please define delays in the parent Device Settings or in the superior Group Settings .

Access Rights

User Group Access

Define which user group(s) will have access to the object you're editing. A table with user groups and types of access rights is shown: It contains all user groups from your setup. For each user group you can choose from the following access rights:

  • Inherited : Use the access rights settings of the parent object.
  • None : Users in this group cannot see or edit the object. The object neither shows up in lists nor in the device tree. Exception: If a child object is visible to the user, the object is visible in the device tree, though not accessible.
  • Read : Users in this group can see the object and review its monitoring results.
  • Write : Users in this group can see the object, review its monitoring results, and edit the object's settings. They cannot edit access rights settings.
  • Full : Users in this group can see the object, review its monitoring results, edit the object's settings, and edit access rights settings.

You can create new user groups in the System Administration—User Groups settings. To automatically set all objects further down in the hierarchy to inherit this object's access rights, set a check mark for the Revert children's access rights to inherited option.

For more details on access rights, please see the section User Access Rights .

More

Knowledge Base: How do SNMP, MIBs and OIDs work?

Knowledge Base: How can I import my MIB files into PRTG?

Knowledge Base: Can't find a sensor for my device in PRTG but I believe it supports SNMP. How to proceed?

Knowledge Base: How can I monitor EMC Isilon storage systems with PRTG?

Knowledge Base: My SNMP sensors don't work. What can I do?

Edit Sensor Channels

To change display settings, spike filter, and limits, switch to the sensor's Overview tab and click the gear icon of a specific channel. For detailed information, please see the Sensor Channels Settings section.

Notifications

Click the Notifications tab to change notification triggers. For detailed information, please see the Sensor Notifications Settings section.

Others

For more general information about settings, please see the Object Settings section.

Sensor Settings Overview

Feedback / Questions
Copyright © 1998 - 2017 Paessler AG