Ping test to wan

General
1

Hi,

We have check_mk set to ping ISP wan ip to check internet connection.
I am new in company and now one knows how this even works.
“Problem” is that check_mk server doesn’t have connection to WAN. So how can this work?
I was assuming that some server whit connection to our DMZ network, ping ISP ip and then give data to check_mk?
If I look settings for this service, only setting is ping to wan address.
Why am trying to figure it out this?
We did have some major downtime due the UPS failure.
After we turn back on all hypervisors and VMs, check_mk was still showing that main wan connection is down. Connection was fine, only check_mk was not able to detect it.
After few hours, check_mk starts showing ping to WAN is OK.
Is my theory correct, that some server in DMZ have installed agent that can “help” check_mk to detect WAN connections?
How can I check how this ping works and why check_mk was not able to ping WAN address for few hours after failure of basically whole datacenter.

PS: in general check_mk was really great help in this failure situation. Without it, process of turning back on whole datacenter will be even more painful.
Great product!

2

Well CheckMK doesn’t have a kind of magic to connect to other unreachable networks. So most likely some routes were setup so it can reach the WAN. Bit hard to tell without having a look at your setup. From the CheckMK server try a tracert to the WAN address and see what switches it passes. That might give you some insight on what mysterious route there is.

3

Thanks, will check it with tracert

4

Thanks again. With tracert I figured out, that check_mk have (limited) access to internet.

5

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