access-user arp-detect default ip-address

Usage Scenario

The device sends an ARP probe packet to check the user online status. If the user does not respond within a detection period, the device considers that the user is offline.

Precautions

• Only wired users support this function.

• This function does not take effect for users who use Layer 3 Portal authentication.

• In the SVF or policy association scenario, you are advised to run the access-user arp-detect default ip-address command to set the source IP address of offline detection packets to 0.0.0.0. In the SVF scenario, the command must be configured on the control device and takes effect only for control device detection. The default source IP address of offline detection packets for access device detection is 0.0.0.0. In the policy association scenario, you can directly configure the command on access devices.

• In normal situations, after a device sends an ARP probe packet with a default source IP address, online clients will immediately respond with ARP reply packets. If online clients do not respond with ARP reply packets, the device logs them out unexpectedly. To resolve this problem, use either of the following methods:

  • Run the access-user arp-detect vlan vlan-id ip-address ip-address mac-address mac-address command to specify a VLAN ID, source IP address, and source MAC address for ARP probe packets.
  • Run the authentication timer handshake-period handshake-period command to increase the handshake period so that the device can detect gratuitous ARP packets that these clients send at an irregular period. Once the device detects such packets, it does not log them out.