Notifications from Monitoring in Plesk: The bandwidth utilization status is critical!

Leonardo Neissinger Soares

Updated June 16, 2026 22:15

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Applicable to:

Plesk for Linux
Plesk for Windows

Question

What should be done upon receiving a notification from Monitoring about critical bandwidth utilization in Plesk? E.g.:

PLESK_WARN: The threshold of interface "eth0" throughput has been exceeded.
The bandwidth utilization status is critical!
The current value is XX.XX packets/sec.

Answer

This notification informs the Plesk administrator that bandwidth utilization on one of the server's network interfaces exceeds the threshold values configured in Monitoring > Settings > Thresholds > Network.

There are two possible reasons for this alert:

The bandwidth load is expected, but the threshold is set too low.
The bandwidth load is unexpected and requires further investigation.

How to investigate.

Check the bandwidth utilization threshold values for alerts at Monitoring > Settings > Thresholds > Network.
Estimate the current bandwidth utilization using the following utilities:
For Linux: lsof, iftop or netstat.
For Windows: TaskManager, Resource Monitor or other 3rd-party solutions for analyzing the network traffic, such as Wireshark.
Use the gathered data for further analysis:
- If the bandwidth load is expected, determine the optimal threshold values — ones that are above the average load but not critical. Adjust the thresholds at Monitoring > Settings > Thresholds.
- If the bandwidth load is expected but is causing server performance issues, consider increasing the server's network bandwidth — for example, if the server is virtual and bandwidth is managed at the virtualization node level.
- If the bandwidth load is unexpected, investigate the cause of the high network traffic:
  - Pay attention to prolonged network activity spikes.
  - Unexpected incoming traffic may indicate that the server is under attack. Investigate for a potential DoS/DDoS attack.
  - Unexpected outgoing traffic may indicate that the server is a source of spam, has been compromised, or is infected with malware and is being used to attack other servers. Investigate for potential spam activity.