Network Interface Check Reference

Configuration options for the network interface check

Written By Erdinc Akay

Last updated About 1 month ago

The network interface check monitors the health of network adapters including link status, speed, packet errors, and losses.

Configuration fields

Field	Type	Required	Default	Description
Interface names	List of strings	No	— (empty = all active non-loopback)	Specific interfaces to monitor. Leave empty to monitor all active non-loopback interfaces.
Warning error rate (%)	Percent	No	0.1	Packet error rate that triggers a warning
Critical error rate (%)	Percent	No	1.0	Packet error rate that triggers a critical result
Warning drop rate (%)	Percent	No	0.1	Packet drop rate that triggers a warning
Critical drop rate (%)	Percent	No	1.0	Packet drop rate that triggers a critical result
Expected speed (Mbps)	Mbps	No	0 (disabled)	Minimum expected link speed; produces a warning when the measured speed is below this value
Alert on link down	Boolean	No	Yes	Raise a critical alert when an interface link is down
Exclude virtual adapters	Boolean	No	Yes	Exclude virtual adapters (VPN, Docker, Hyper-V, VMware, etc.) from monitoring

Loopback interfaces are always excluded. Virtual adapters (VPN, Docker bridges, Hyper-V, VMware, vEthernet, tun/tap, etc.) are excluded by default; clear Exclude virtual adapters to include them.
On a Hyper-V guest, Exclude virtual adapters keeps the machine's real network adapter. A guest's primary NIC reports as "Microsoft Hyper-V Network Adapter" and is kept, while the host-side virtual switch (a "Hyper-V Virtual Ethernet Adapter" named "vEthernet (...)") is still filtered out as genuinely virtual.
Error and drop rates are cumulative since the interface came up — total error/drop counters divided by total packets, not the rate observed in the last polling interval.
With Alert on link down enabled (the default), interfaces that are down are still included so they can raise a critical alert. Only when it is disabled are non-active interfaces filtered out of monitoring.
The check runs every 5 minutes on the agent. The interval is not user-configurable.