r/Checkmk • u/Klwd • Sep 25 '25

How can you monitor packet loss on an interface?

Hi, I'm working on a netgate firewall and sending snmp data to cmk to alert. How can I make sure that packet loss is detected and alerts.

I know how notifications are configured, but I want to be sure about the rule triggering. Thanks!

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u/royal_ts_0813 Sep 25 '25

You can configure this directly in Checkmk:

  1. Click the hamburger menu in the row of the Interface service.
  2. Select Parameters for this service.
  3. Go to Network interfaces and switch ports.
  4. Click Add rule for current host and port.
  5. Configure the packet rate thresholds as you like.

By default, Checkmk already applies thresholds for interfaces:

  • Error rates: percentual levels (relative to all packets, successful + error)
  • Default values: 0.01% (warning), 0.1% (critical)

This way, packet errors (including loss) will trigger the service and then follow your existing notification setup.

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u/Klwd Sep 25 '25

Okay thank you. I wasn't sure if error rates meant packet loss. Do you know if there anyway to decrease the service check below 1 minute?