Monitoring cisco switch interface trunk and vlan information

General
1

Hi All,

i hope I’m able to narrow down the issue as I’m still quite new to Checkmk and monitoring in general. I saw this blog post here: Network Monitoring with Checkmk: 3 rules to rule them all
But i would like to take a different approach than naming interfaces.

I would like to monitor all interfaces in switchport mode trunk and a specific switchport access vlan. So far i got a checkmk to get data from a cisco switch via SNMP v3. I can read interface Status, mac and Speed. In addition to that of course also some SNMP, uptime or interface vlan information. Im still missing information about trunk and access vlan.

I tried to find out if that information is included in the data via an snmp walk and mib browser.
The MIB Browser brought some information about the access vlans I’m searching but so far i wasn’t able to get it in a readable format. Not sure if I’m missing a special MIB file but the MIB locator from cisco didn’t provide me with any result. Various changes in “Network interface and switch port discovery“ also didn’t provide the wanted information.

Is there any way to archive this?
Thanks in advance!

2

I think there is no easy way to achieve this.

3

I never saw this beeing achieved :frowning:

As logic you should be able to add the interface in monitoring only if interface have the switchport access vlan ABC .

I think this could be a nice feature to add … (maybe add a suggestion here: https://ideas.checkmk.com/ )

4

Thanks to both of you!

just to be clear here: is it also impossible to receive trunk and vlan data of every interface?
Maybe I’m remembering incorrectly but i could have sworn i saw this at a other company.

5

It is not impossible, the only question here is from where do you can get this information.
The second step would be then to look if there is already a check or inventory plugin that fetches these information. If not a new check or inventory plugin needs to be created.

I think what you want (trunks and vlans) is already existing. Please switch on the HW/SW inventory for these devices and take a look at the fetched data inside HW/SW inventory. You should see the interface table and vlan interfaces and trunk interfaces should be shown there.

If you want to monitor these you need to modify the “Interface and switch port discovery” rule.
But i would say it makes no sense to monitor vlan interfaces on a normal switch. Trunk interfaces should work fine.

6

I have spent some time with the inventory. For some Switches interface Vlan comes up for others not, depending on the model. Trunking information never came up.

I may be at the end what i currently can find out. Could be that i need to consult somebody over this or stick with the naming. Didnt think this would be so hard.