Enables gratuitous ARP protection on one or all VLANs on the switch.
| all | Specifies all VLANs configured on the switch. |
| vlan_name | Specifies the VLAN. |
| dynamic | Configuration options for dynamically created VLANs. |
By default, gratuitous ARP protection is disabled.
Dynamic VLAN option added in ExtremeXOS 30.2.
Beginning with ExtremeXOS 11.6, this command replaces the enable iparp gratuitous protect command.
Hosts can launch man-in-the-middle attacks by sending out gratuitous ARP requests for the router's IP address. This results in hosts sending their router traffic to the attacker, and the attacker forwarding that data to the router. This allows passwords, keys, and other information to be intercepted.
To protect against this type of attack, the router will send out its own gratuitous ARP request to override the attacker whenever a gratuitous ARP broadcast with the router's IP address as the source is received on the network.
Beginning with ExtremeXOS 11.6, if you enable both DHCP secured ARP and gratuitous ARP protection, the switch protects its own IP address and those of the hosts that appear as secure entries in the ARP table.
To display information about gratuitous ARP, use the following command:
show ip-security arp gratuitous-protectionThe following command enables gratuitous ARP protection for VLAN corp:
enable ip-security arp gratuitous-protectection vlan corp
This command was first available in ExtremeXOS 11.6.
Dynamic VLAN option added in ExtremeXOS 30.2.
This command is available on ExtremeSwitching 5320, 5420, 5520, and 5720 series switches.