556 CHAPTER 30: ARP CONFIGURATIONoverwrite static ARP entries, and dynamic ARP entries cannot overwrite authorizedARP entries. The aging mechanism of authorized ARP entries is independent fromthat of dynamic ARP entries.Configuring AuthorizedARPEnabling authorized ARPFollow these steps to enable authorized ARP:Configuring the aging time for authorized ARP entriesFollow these steps to configure the aging time for authorized ARP entries:Example for ConfiguringAuthorized ARP on aDHCP ServerNetwork requirements■ Router A acts as a DHCP server with an IP address pool of 10.1.1.0/24.■ Router B is a DHCP client which obtains an IP address of 10.1.1.2/24 from theDHCP server.Network diagramFigure 157 Network diagram for authorized ARP configurationConfiguration procedure1 Configure Router A# Configure the IP address of Ethernet 1/0. system-view[RouterA] interface ethernet 1/0[RouterA-Ethernet1/0] ip address 10.1.1.1 24[RouterA-Ethernet1/0] quit# Configure DHCP.To do... Use the command... RemarksEnter system view system-view -Enter interface view interface interface-typeinterface-number-Enable authorized ARP on theinterfacearp authorized enable RequiredNot enabled by default.To do... Use the command... RemarksEnter system view system-view -Enter interface view interface interface-typeinterface-number-Configure the aging time forauthorized ARP entriesarp authorized time-outsecondsOptional1200 seconds by default.DHCPclientDHCPserverRouter A Router BEth1 /010 .1 .1.1/24 Eth1/0
