Checkmk snmp doubt

Hello there,

I am new to checkmk and I am looking for help to resolve a specific problem I am facing.

We have successfully configured the checkmk using the web interface it provides, so it can monitor the amount of network packets going through different Cisco Switches.

Apparently, there is a default snmp OID that checkmk uses to get to know the number of packets going through this Cisco firewall.

I would like to know which is this default configuration that checkmk is using by default to query via snmp all of this information.

If you need any more information, do not hesitate to ask.

Thanks in advance!

If you want to know the specific OIDs checkmk uses to query the SNMP agent you have to look at the check plugin implementation. The plugins are found in $OMD_ROOT/share/check_mk/checks/.

Hello Robert,

First of all, thank you for your quick response!

I would like to say a few things:

  • There seems to be only two plugins available related to snmp:
    snmp_info snmp_uptime

Looking these two plugins I can see the following OIDs are used:

Specifically the OIDs:
.1.3.6.1.2.1.1.1.0: sysDescr.0
.1.3.6.1.2.1.1.4.0: sysContact.0
.1.3.6.1.2.1.1.5.0: sysName.0
.1.3.6.1.2.1.1.6.0: sysLocation.0

How is it able to get the number of packets going through a cisco device?

Btw the version of checkmk I am using is the following: 1.5p20

Thanks for your help!

No, there are many more. grep for snmp_info in that folder.
Have a look at the service check in question. It displays the used check plugin in its details. This way you can have a direct look at the file.

Good morning Robert,

My mistake, there seems to be way more plugins using snmp than just 2. :sweat_smile:

Is there any specific documentation I can follow to see the description of all this plugins?

Thanks for all your help, you are really shedding some light on this matter,

Unfortunately there is currently no documentation available online as the old docs have been pulled from the website.

There is still something in the web archive at http://web.archive.org/web/20180804153330/http://mathias-kettner.com/checkmk.html
Especially part 7 “Writing extensions” with its chapters about SNMP could be of interest.

Every check should have a “manual page” with a short explanation.
(a plugin may yield one or more checks)

In WATO, there’s a section for all the check plugins that you can browse and search:

https://SERVER/SITE/wato.py?folder=&mode=check_plugins

This catalog of check plugins gives you a complete listing of all plugins that are shipped with your Check_MK installation. It also allows you to access the rule sets for configuring the parameters of the checks and to manually create services in case you cannot or do not want to rely on the automatic service discovery.

Hello guys,

Thank you for solving me these doubts. Eventually I managed to understand how the code of this extensions worked and how it related to checkmk. You really are a great community.

Thanks!

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