The access-user arp-detect fallback command configures an IP address required for calculating the source address of offline detection packets.
The undo access-user arp-detect fallback command deletes the IP address configured for calculating the source address of offline detection packets.
By default, no IP address is configured for the device to calculate the source address of offline detection packets.
access-user arp-detect fallback ip-address { mask | mask-length }
undo access-user arp-detect fallback
Parameter |
Description |
Value |
|---|---|---|
ip-address |
Specifies the IP address required for calculating the source address of offline detection packets. |
The value is in dotted decimal notation. |
mask |
Specifies the mask of the IP address. |
The value is in dotted decimal notation. After the mask is converted into a binary number, all bits before the last 1 must be 1s. That is, 1s in the mask must be continuous and there cannot be any 0s before the last 1. |
mask-length |
Specifies the mask length of the IP address. |
The value is an integer in the range from 0 to 32. |
Usage Scenario
When the device does not function as a gateway, it can send offline detection packets with the source address on the same network segment as clients. This source address is calculated based on the client network segment and the IP address specified in the access-user arp-detect fallback command. The operation AND is performed between this specified IP address and the wildcard mask to obtain result 1. Then result 1 is added to the network segment of clients to get the source address of offline detection packets. For example, if the network segment of clients is 192.168.1.0/24 and access-user arp-detect fallback 0.0.0.11 24 is configured, the source address of offline detection packets is 192.168.1.11. The calculated source address must be excluded from the address pool of the DHCP server to prevent IP address conflicts.
Precautions
Only wired users support this function.
This function does not take effect for users who use Layer 3 Portal authentication.
This command is effective for online users connected to physical interfaces only after the users go online again or the device re-authenticates the users.