Configuring ARP Entry Fixing
Context
- fixed-mac: When receiving an ARP packet, the device discards the packet if the MAC address does not match that in the corresponding ARP entry. If the MAC address in the ARP packet matches that in the corresponding ARP entry while the interface number or VLAN ID does not match that in the ARP entry, the device updates the interface number or VLAN ID in the ARP entry. This mode applies to networks where user MAC addresses are unchanged but user access locations often change. When a user connects to a different interface on the device, the device updates interface information in the ARP entry of the user timely.
- fixed-all: When the MAC address, interface number, and VLAN ID of an ARP packet match those in the corresponding ARP entry, the device updates other information about the ARP entry. This mode applies to networks where user MAC addresses and user access locations are fixed.
- send-ack: When the device receives an ARP packet with a changed MAC address, interface number, or VLAN ID, it does not immediately update the corresponding ARP entry. Instead, the device sends a unicast ARP Request packet to the user with the IP address mapped to the original MAC address in the ARP entry, and then determines whether to change the MAC address, VLAN ID, or interface number in the ARP entry depending on the response from the user. This mode applies to networks where user MAC addresses and user access locations often change.
- If ARP entry fixing is enabled globally, all interfaces have this function enabled by default.
- If ARP entry fixing is enabled globally and on an interface simultaneously, the configuration on the interface takes precedence over the global configuration.
Procedure
- Configure ARP entry fixing globally
- Configure ARP entry fixing on an interface
- On an Ethernet interface, run undo portswitch
The interface is switched to Layer 3 mode.
By default, an Ethernet interface works in Layer 2 mode.
The mode switching function takes effect when the interface only has attribute configurations (for example, shutdown and description configurations). Alternatively, if configuration information supported by both Layer 2 and Layer 3 interfaces exists (for example, mode lacp and lacp system-id configurations), no configuration that is not supported after the working mode of the interface is switched can exist. If unsupported configurations exist on the interface, delete the configurations first and then run the undo portswitch command.
If many Ethernet interfaces need to be switched to Layer 3 mode, run the undo portswitch batch interface-type { interface-number1 [ to interface-number2 ] } &<1-10> command in the system view to switch these interfaces to Layer 3 mode in batches.
- On an Ethernet interface, run undo portswitch
