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https://docs.sophos.com/nsg/switch/help/en-us/index.html?contextId=user-guide-features-configure-poe-keepalive

PoE keepalive

PoE keepalive allows the switch to check the status of powered devices and restart them by cycling the PoE power to the port. You can set PoE keepalive globally or individually per PoE port.

Global settings

Select Turned on or Turned off to turn PoE keepalive on or off globally.

Advanced configuration

You can configure and monitor PoE keepalive settings for individual ports on the Advanced configuration tab. You can sort each setting by clicking the column header.

To change the PoE settings for the switch's ports, select the ports you want to configure and click Edit. Make your changes, then click Apply to save the settings.

The PoE keepalive settings are as follows:

  • Port: The number of the port on the switch.
  • Status: This shows whether PoE keepalive is turned on or off for the specified port.

  • Mode: The PoE keepalive mode for the specified port. Choose from the following options:

    • Auto: The switch uses LLDP to check the status of a powered device. It switches to ping when it can't reach the powered device using LLDP.
    • Force Ping: The switch pings the powered device to determine its online status.

  • Specified IP address: You can specify an IP address for the switch to check for PoE keepalive mode.

  • Ping interval: The time, in seconds, between pings. It must be between 1 and 3600.
  • Ping: Maximum number: The maximum number of failed pings before the powered device is restarted. It must be between 1 and 255.

  • Action type: The response to take when a powered device goes offline. Choose from the following options:

    • Reboot with Syslog: The switch restarts the powered device and generates a syslog message.
    • Syslog: The switch generates a syslog message when a powered device goes offline but doesn't restart it.

  • Power recovery interval: The time, in seconds, that the switch turns off PoE to the port during a restart. It must be between 1 and 600.

You can choose additional PoE keepalive information to show on the Advanced configuration tab. Click the ellipsis Ellipsis. and select the information you want to show from the following options:

  • Maximum number of restarts: The maximum restart attempts when a powered device remains offline. You can uncheck the box to allow the switch to restart unresponsive powered devices continuously.
  • Restart count: The number of times the switch has tried restarting a powered device. Select Refresh to reset the restart count column.
  • PoE startup time: The time, in seconds, after a restart before the switch starts checking the status of a powered device. It must be between 50 and 1200.
  • LLDP retention time: The amount of time, in seconds, the switch keeps LLDP packets before they expire. It must be between 30 and 600.

Status of supplying port

You can monitor the PoE keepalive status of PoE ports on the Status of supplying port tab. Click Refresh to update the information shown.

The information shown is as follows:

  • Port: The number of the port on the switch.
  • Status: Shows the PoE status of the specified port.
  • Mode: The PoE keepalive mode for the specified port.
  • Polling method: The switch's method for checking the powered device status.
  • MAC address: The MAC address of the powered device connected to the specified port.
  • Management IP address: The management IP address of the powered device connected to the specified port.
  • Action taken: The switch's last PoE keepalive action on the powered device.