The access-user arp-detect command sets the source IP address and source MAC address of offline detection packets in a VLAN.
The undo access-user arp-detect command deletes the source IP address and source MAC address of offline detection packets in a VLAN.
By default, the source IP address and source MAC address are not specified for offline detection packets in a VLAN.
access-user arp-detect vlan vlan-id ip-address ip-address mac-address mac-address
undo access-user arp-detect vlan vlan-id ip-address ip-address mac-address mac-address
Parameter |
Description |
Value |
|---|---|---|
vlan vlan-id |
Specifies a VLAN ID. |
The value is an integer that ranges from 1 to 4094. |
ip-address ip-address |
Specifies the source IP address of offline detection packets. |
The value is in dotted decimal notation and can be 0.0.0.0 or 255.255.255.255 or other valid IP address. |
mac-address mac-address |
Specifies the source MAC address of offline detection packets. |
The value is a unicast MAC address in H-H-H format, where H can be one to four hexadecimal digits. |
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.
If the VLAN to which the user belongs does not have a VLANIF interface or the VLANIF interface does not have an IP address, the device sends an offline detection packet using 0.0.0.0 as the source IP address. If a user cannot respond to an ARP probe packet with the source IP address 0.0.0.0, you can specify a source IP address for the offline detection packet.
In addition, a Windows client sends an ARP probe packet with the source IP address 0.0.0.0 after obtaining an IP address. In this case, if the device also sends an ARP probe packet with the source IP address 0.0.0.0, an IP address conflict occurs. In this case, you can specify an IP address as the source IP address of ARP probe packets sent by the device.
You are advised to specify the user gateway IP address and its corresponding MAC address as the source IP address and source MAC address of ARP probe packets sent by the device. If the gateway device changes, update the source MAC address of the ARP probe packets sent by the device in a timely manner. Otherwise, the gateway ARP entry on terminals may be incorrect, causing network disconnection.
Precautions
Only wired users support this function.
This function does not take effect for users who use Layer 3 Portal authentication.
If a user on a physical interface is online, this command takes effect only after the user goes online again or the device re-authenticates the user.