SNMP by MIB Monitor

The SNMP by MIB Monitor allows you to monitor objects on any SNMP agent. The error and warning thresholds for the monitor can be set on as many as ten different objects.

Usage Guidelines

The SNMP by MIB Monitor operates like many other browsable monitors: it gathers information from a source, organizes it into a browsable tree structure, and allows the user to choose which items in the tree it should monitor. It works by connecting to the specified SNMP agent and performing a full traversal of the MIB(s) implemented by the agent. Thus, the user does not need to know which objects are present on the agent in advance.

The MIB files in SiteScope/templates.mib are then used to create a browsable tree that contains names and descriptions of the objects found during the traversal. Note that an object may or may not be displayed with a textual name and description, depending on the MIBs available in SiteScope/templates.mib. SiteScope does not display objects for user selection when it has no knowledge of how to display those objects. For example, a plain OctetString may contain binary or ascii data, but SiteScope has no way to decode and display this data correctly without more information.

The default run schedule for this monitor is every 10 minutes, but you can change it to run more or less often using the Update every setting.

Completing the SNMP by MIB Monitor Form

To display the SNMP by MIB Monitor Form, either click the Edit link for an existing SNMP by MIB Monitor in a monitor table, or click the add a Monitor link on a group's detail page and choose the "Add SNMP by MIB Monitor" link.

Complete the items on the SNMP by MIB Monitor Form as follows. When the required items are complete, click the Add Monitor button.

Server: Enter the name of the server you want to monitor.
MIB File: Select the MIB file which contains the objects you are interested in monitoring. If you select a specific MIB file, then only the objects described in that MIB file are displayed. If you select "All MIBs", then all objects retrieved from the agent during the MIB traversal will be displayed. If no MIB information is available for an object, it is still displayed, but with no textual name or description. To make this monitor aware of new or additional MIBs, simply place new MIB files in the SiteScope/templates.mib directory.
SNMP Version: Select the version of SNMP to use when connecting.
Community: Enter the community string (valid only for version 1 or 2 connections).
SNMP V3 Authentication Type: Select the type of authentication to use for version 3 connections.
SNMP V3 Username: Enter the username for version 3 connections.
SNMP V3 Authentication Password: Enter the authentication password to use for version 3 connections.
SNMP V3 Privacy Password: Enter the privacy password if DES privacy encryption is desired for version 3 connections. Leave blank if you do not want privacy.
SNMP V3 Context Engine ID: Enter a hexidecimal string representing the Context Engine ID to use for this connection. This is applicable for SNMP V3 only.
SNMP V3 Context Name: Enter the the Context Name to use for this connection. This is applicable for SNMP V3 only.
Counters: Choose the counters (objects) you want to check with this monitor. The table list to the right of this item displays those currently selected for this monitor. Use the choose counters link to bring up the counters selection screen. Check or clear the check boxes on the choose counters screen to select between one to ten counters to monitor on this server.
Update every: Enter how frequently the monitor should read the server statistics. The drop-down list to the right of the text box lets you specify time increments of seconds, minutes, hours, or days. You must specify a time increment of at least 15 seconds.
Title (Optional): Enter a name for this monitor. This name appears in the Name text box on the monitor table when you open the group's detail page. If you don't enter a name, a default name will be created.

Advanced Options

The advanced options give you the ability to customize error and warning thresholds. If you choose not to set them, SiteScope will use pre-set defaults if available. If a default is not available, SiteScope will not be able to utilize the condition.

Disable

Check this box to temporarily disable this monitor and any associated alerts. To enable the monitor again, clear the box.

Timeout

Enter the total time, in seconds, that SiteScope should wait for all SNMP requests (including retries) to complete.

Retries

Enter the number of times each SNMP GET request should be retried before SiteScope considers the request to have failed.

Port

Enter the port to use when requesting data from the SNMP agent. The default of 161 is the port on which an SNMP agent will typically be listening.

Counter Calculation Mode

Use this option to perform a calculation on objects of type Counter, Counter32, or Counter64. The available calculations are:

a simple delta of the current value from the previous value, OR
a rate calculation using the delta of current value from previous value, divided by the time elapsed between measurements

Note: This option only applies to the aforementioned object types. An SNMP by MIB Monitor that monitors Counter objects as well as DisplayString objects will only perform this calculation on the Counter objects.

Verify Error

Check this box if you want SiteScope to automatically run this monitor again if it detects an error. When an error is detected, the monitor will immediately be scheduled to run again once.

Note: In order to change the run frequency of this monitor when an error is detected, use the Update every (on errors) option below.

Note: The status returned by the Verify Error run of the monitor will replace the status of the originally scheduled run that detected an error. This may cause the loss of important performance data if the data from the verify run is different than the initial error status.

Warning: Use of this option across many monitor instances may result in significant monitoring delays in the case that multiple monitors are rescheduled to verify errors at the same time.

Update Every (on error)

This options allows you to set a new monitoring interval for monitors that have registered an error condition. For example, you may want SiteScope to monitor this item every 10 minutes normally, but as often as every 2 minutes if an error has been detected. Note that this increased scheduling will also affect the number of alerts generated by this monitor.

Schedule (Optional)

By default, SiteScope's monitors are enabled every day of the week. You may, however, schedule your monitors to run only on certain days or on a fixed schedule. Choose the Edit schedule link to create or edit a monitor schedule. For information about creating schedules, read these instructions.

Monitor Description (Optional)

Enter additional information about this monitor. The Monitor Description can include HTML tags such as the <BR> <HR>, and <B> tags to control display format and style. The description will appear on the Monitor Detail page.

Report Description (Optional)

Enter a description for this monitor that will make it easier to understand what this monitor does. The description will appear on Management Reports and on the info pop-up for a monitor.

Depends On (Optional)

To make the running of this monitor dependent on the status of another monitor or monitor group, use the drop-down list to select the monitor on which this monitor is dependent. Select None to remove any dependency.

Depends Condition (Optional)

If you choose to make the running of this monitor dependent on the status of another monitor, choose the status condition that the other monitor or monitor group should have in order for the current monitor to run normally. The current monitor will be run normally as long as the monitor on which it depends reports the condition selected in this option.

List Order (Optional)

By default, new monitors are listed last on the Monitor Detail page. You may use this drop-down list to choose a different placement for this monitor.

Setting Monitor Status Thresholds

SiteScope Application Monitors allow you to set multiple threshold conditions to determine the status reported by each monitor. The individual conditions are combined as logical OR relationships so that when one or more of the conditions (for example any of the conditions for Error if) are met the monitor status is set to the applicable condition. If multiple conditions are met for more than one status condition (such as conditions for both error and for warning), the status for the monitor is set to the highest valued condition. Thus a match of an error condition and a warning condition would be reported as an error status, error being the highest value, warning the next highest and good the lowest value.

Error if: Use one or more of the selection boxes in this item to define one or more error conditions for this monitor. Use the drop-down lists in these items to change error threshold(s) relative to the counters you have selected to check with this monitor. After choosing a counter or parameter, use the comparison operator drop-down list to specify an error threshold such as: >= (greater than or equal to), != (not equal to), or < (less than) and enter a comparison value in the box provided. Comparison values should be entered as whole numbers.
Warning if: Use one or more of the selection boxes in this item to define one or more warning conditions for this monitor. Use the drop-down lists in these items to change warning threshold(s) relative to the counters you have selected to check with this monitor. Set these values relative to those you set for the error threshold in the Error if item.
Good if: You can set this monitor to return a good status for certain conditions. You may define those conditions here. Complete this item as you would for the Error if and Warning if items.

Troubleshooting MIB Compilation

As mentioned above, you can add to the MIBs of which SiteScope is aware by putting new MIB files in the templates.mib directory. In order to recompile any new MIBs, you must restart SiteScope. Unfortunately, since MIB files may depend on other MIB files, and because ASN.1 syntax is not always obeyed completely by vendors, you may encounter compilation errors with some MIBs. Below is a series of steps you can follow when compiling new MIBs and troubleshooting compilation failures:

Add new MIB files to the templates.mib directory. SiteScope only compiles MIBs in ASN.1 format which abide by the SMIv1 or SMIv2 standards.
Restart SiteScope.
Proceed as if to add a new SNMP by MIB Monitor. Before adding the monitor, check to see that your new MIB files are listed in the MIB File dropdown box. If they are, then they were successfully compiled and you may now use the SNMP by MIB monitor and the SNMP by MIB tool to browse devices that implement these MIBs. If your newly added MIBs are not listed in the MIB File dropdown box, then proceed to the next step.
Open the file error.log in the logs directory. Look for error messages about MIB compilation near the time of your most recent restart. The error messages in this file contain descriptions of compilation errors encountered per file. The line numbers are included in these error messages, so identifying the source of the errors should not be very difficult.
Correct the errors found in error.log. Usually, these errors can be fixed by one of the following:
- Adding a MIB to templates.mib on which some of the new MIBs depend.
- Removing a MIB from templates.mib which is duplicated or upgraded in the new MIBs.
- Fixing broken comments in the new MIBs. Note that a comment is defined as follows: "ASN.1 comments commence with a pair of adjacent hyphens and end with the next pair of adjacent hyphens or at the end of the line, whichever occurs first." This means that a line containing only the string "-----" is a syntax error, whereas the a line containing only the string "----" is a valid comment. Beware of lines containing only hyphens, as adding or subtracting a single hyphen from such lines may break compilation for that MIB.
- Fixing missing IMPORT statements. Some MIBs may neglect to import objects that they reference which are defined in other MIBs.
After correcting the errors described in error.log, restart SiteScope and follow the procedure above to verify that the new MIB files compiled correctly.