undo arp learning ip-network-cross enable
Function
The undo arp learning ip-network-cross enable command disables inter-network segment ARP learning on interfaces.
By default, inter-network segment ARP learning is disabled on interfaces.
Only the S5720-EI, S5720-HI, S5730-HI, S5731-H, S5731-S, S5731S-H, S5731S-S, S5732-H, S5735-L, S5735S-L, S5735S-L-M, S5735-S, S5735S-S, S5735-S-I, S6720-EI, S6720-HI, S6720S-EI, S6730-H, S6730S-H, S6730-S, and S6730S-S support this command.
Usage Guidelines
If the system software of a switch is upgraded from V200R005C00 or a later version to V200R010C00SPC600 or a later version, inter-network segment ARP learning is enabled on interfaces by default. If you run the display this include-default command in the system view after the configuration is restored, the command output includes arp learning ip-network-cross enable.
In Figure 1, loop prevention protocols have been configured on the switches. Switch can learn the ARP entry containing the IP address 172.16.2.20 of interface IF6 on SwitchB through interface IF2. After proxy ARP is enabled on SwitchA, Switch can learn ARP entries on another network segment, and interface IF1 on Switch can learn the ARP entry containing the IP address 172.16.2.20 of interface IF6 on SwitchB. As a result, the ARP entry learned through interface IF2 is overwritten by that learned through interface IF1, and Switch cannot communicate with SwitchB. In this case, you can run the undo arp learning ip-network-cross enable command to disable inter-network segment ARP learning on interface IF1 of Switch.
