A guide on how to monitor Juniper EX switches using SNMP and Opsview.
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How to do an SNMP walk
This guide shows you how to run an SNMP walk in Opsview. An SNMP walk is a simple way to set up the collection of information from your routers, switches or other SNMP enabled devices. The SNMP walk will allow you to see all of the OID parameters available on your SNMP device and then set rules against the values.
In order to run the SNMP walk and set up the monitoring there are only 3 steps that you need to perform:
- Loading MIB files
- Adding the host
- Running the SNMP walk
Loading MIB files
MIB files link each OID to human readable definitions -- these files are normally provided by the device vendor. While this step is not mandatory, adding MIB files makes it a lot easier to choose the appropriate OID parameters for your rules. You can find the procedure to load MIB files here.
Adding the host
Before running the SNMP Walk we need to add the host and enable SNMP monitoring for it. To add a new host it suffices to specify the IP, a unique name and a host template – you can find a more detailed guide here. We advise you to add the SNMP - MIB-II host template as this will provide essential monitoring of the SNMP interface.
To enable SNMP monitoring go to the SNMP tab on the host config modal and tick the Enable SNMP checkbox; then select the SNMP version and the SNMP port. Depending on the SNMP version you chose you will have to define either the community string (v1, v2c) or the various SNMP v3 credentials (v3) . Be sure to use the Test SNMP Connection to ensure the connection to the SNMP device is going to work.
Running the SNMP walk
To run the SNMP walk we need to add a new SNMP polling service check or to edit an existing one. When adding the new service it suffices to specify the name - you can find more about the other options here.
On the SNMP Polling tab fill in the Example Host with the host created on the previous step and click Rescan - this will run a SNMP walk on the host you selected.
You can then select one OID from the table by clicking the line – this will automatically fill the OID and the Label fields. Finally you can add a rule that will control the status of service check based on the value returned for the OID.
You can create multiple SNMP Polling service checks, each tracking a specific parameter of your device. Additionally you can then combine them into a host template and apply it to multiple similar devices but be sure the devices share the same MIB files or the rules will not be applicable.
This is how easy it is go get your SNMP devices monitored in no time.
Opsview also supports SNMP Traps which provide passive monitoring of a SNMP device. Unlike SNMP polling checks which are actively run by Opsview, with SNMP Traps you configure your devices to report into Opsview. You can find more information about SNMP Trap checks here.