Monitoring interface administrative status

In the short tutorial below, we will set up a SNMP monitor to watch the network interface admin status (testing, up or down). Click on the thumbnail pictures provided to view their full version.

Introduction

IPHost Network Monitor can work with all the SNMP versions (see in the monitor properties editor section). Note that the version 1 isn’t recommended in general, due to multiple security issues.
IPHost Network Monitor allows to monitor exact value, test if the value has changed, or whether the value is valid.
There’s a powerful MIB browser tool, allowing to navigate the entire collected OIDs tree. It can be used either from “Tools” menu item…
…or by clicking Select button to the right of OID value, in the monitor properties editor.
MIB browser allows to

  • display and navigate OID hierarchy (in tree-like form)
  • set the specified elements to new values (the values that may be changed are displayed on a green background)
  • load or unload MIB files containing definitions of elements
  • search by numerical OID values or by their literal names

 

Starting SNMP services on the host

Detailed explanation how to set up, configure and start SNMP services on the host machine we are about to monitor network interface status on is outside the scope of this tutorial.

Note that not every device is capable of supporting IP stats parameters; make sure the device supports these statistical data first. Most network hardware, computers etc. do support those.

You should look for documentation on software packages such as net-snmp and/or firewall settings to have SNMP services be set up correctly and securely. Further on this tutorial we assume you have set up the SNMP services and the computer where IPHost Network Monitor runs is allowed to connect to the device running those services.

 

Creating SNMP monitor

Let’s start to create a SNMP monitor. Let’s add a new host for a network device (computer, router and so on; choose “New Host” from “File” menu item, or right-click on an appropriate hosts group and select “New Host”).
After the new host has been created, right-click on it and select “New Monitor”.
Select “Resources – over SNMP and SSH” category on the left and select “SNMP Custom” monitor type and click “Next”.
On the next screen, specify the host name of the device you’re creating SNMP monitor for. If you are absolutely sure you have all the data at hand, you can also check the “Start the monitor” in the lower left corner, to activate the monitor immediately after its creation. Click “Next”.
On this final screen you can select OID to monitor, upload required MIB(s), set up threshold values to raise alerts and specify all the other parameters for the monitor. The details of setting those up are explained in the section below.

Note that while the new monitor creation wizard is running, you can’t otherwise use IPHost Network Monitor. Click “Finish” after you have completed (or if you choose to set up monitor in the Parameters/Results pane).

 

Setting up monitoring parameters

Launch the MIB browser (see above how to do that) to proceed.

If you haven’t loaded proper MIB file (IP-MIB or rfc1213 should do), the browser will not show you much useful information. Download the mentioned MIB file, click on “MIBs” button (lower left corner of the MIB browser) and look whether the required MIB is loaded already.
If IP-MIB or rfc1213 is present in the list, just skip this step. Otherwise, make sure the downloaded MIB file is placed into %ProgramData%\IPHost Network Monitor\mibs and click on “Import” button. Select the required MIB file and click “Open”.
Now refresh MIB browser main view by clicking “Refresh” button. To find OIDs related to measuring interface(s) admin status, enter word “Admin” to the right of “Find” label. The browser will only display those entries with that word found in literal names.

Note: there can be several interfaces to monitor admin status of. In our case, we choose the first ifAdminStatus entry from the same name branch. Note that you should refer to other IF-MIB entries to make sure you are monitoring the right interface.

You can monitor other entries, as well. In fact, all the important interfaces’ entries should be watched.

Select the mentioned entry and click “OK” to return to monitor Main parameters tab.
Now let’s set up monitor so that it triggered an alarm wherever it changes its normal (‘up’) state.

Open the monitor State Conditions tab om Parameters/Results pane.

Warning state condition is used when the monitored parameter isn’t already acceptable, but the value isn’t that wrong to raise an alarm. Down state condition is used when it is time to raise a real alarm.

Please note that the mentioned entries are read/write, that is, we can enable or disable interface using SNMP, from a program. In our sample, we use ‘testing’ (3) value to send a warning, and ‘down’ (2) to indicate severe performance problem (interface is down).

To learn further how to set up alerts, read Alerting and Actions section of our quick start guide.

 

What to do next?

Congratulations! You have just created your SNMP monitor to notify you when network interface goes down (caveat: if that’s the interface that is used to connect to the same device, you’ll never be able to receive that data). You can now react promptly if that happens and take measures to re-activate the interface. What to do next?
First, set the polling interval on monitor Main parameters tab to appropriate values. Most probably you won’t use the default value of 60 seconds (poll every minute) and could raise it, say, to 5 minutes.
This given case allows little space for variations; however, you can react with calling an external script/whatever (see Alerts section) to enable the interface immediately (thus trying to eliminate the problem and/or collect more data about the failrue).
Please consult the quick start guide for more suggestions and ideas on how to use SNMP monitors.


IPHost Network Monitor 5.4 build 14614 of November 05, 2024. File size: 112MB


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