ARP Commands
649
Command Mode
Global Configuration mode
User Guidelines
When an ARP entry reaches its maximum age, the system must decide
whether to retain or delete the entry. If the entry has recently been used to
forward data packets, the system will renew the entry by sending an ARP
request to the neighbor. If the neighbor responds, the age of the ARP cache
entry is reset to 0 without removing the entry from the hardware. Traffic to
the host continues to be forwarded in hardware without interruption. If the
entry is not being used to forward data packets, then the entry is deleted from
the ARP cache, unless the dynamic renew option is enabled. If the dynamic
renew option is enabled, the system sends an ARP request to renew the entry.
When an entry is not renewed, it is removed from the hardware and
subsequent data packets to the host trigger an ARP request. Traffic to the
host is lost until the router receives an ARP reply from the host. Gateway
entries, entries for a neighbor router, are always renewed. The dynamic renew
option only applies to host entries.
The disadvantage of enabling dynamic renew is that once an ARP cache entry
is created, that cache entry continues to take space in the ARP cache as long
as the neighbor continues to respond to ARP requests, even if no traffic is
being forwarded to the neighbor. In a network where the number of potential
neighbors is greater than the ARP cache capacity, enabling dynamic renew
could prevent some neighbors from communicating because the ARP cache is
full.
Example
console#configure
console(config)#arp dynamicrenew
console(config)#no arp dynamicrenew
arp purge
Use the
arp purge
command in Privileged EXEC mode to cause the specified
IP address to be removed from the ARP cache. Only entries of type dynamic
or gateway are affected by this command.
Summary of Contents for PowerConnect 6224
Page 54: ...54 Contents show ip https 1369 state 1370 ...
Page 134: ...134 Command Groups ...
Page 186: ...186 Using the CLI ...
Page 216: ...216 ACL Commands ...
Page 236: ...236 Address Table Commands ...
Page 250: ...250 CDP Interoperability Commands ...
Page 256: ...256 DHCP Layer 2 Relay Commands Example console config dhcp l2relay vlan 10 340 345 ...
Page 284: ...284 Dynamic ARP Inspection Commands ...
Page 318: ...318 Ethernet Configuration Commands ...
Page 330: ...330 GVRP Commands ...
Page 344: ...344 IGMP Snooping Commands ...
Page 368: ...368 IP Addressing Commands ...
Page 378: ...378 IPv6 Access List Commands ...
Page 386: ...386 IPv6 MLD Snooping Querier Commands MLD Version Indicates the version of MLD ...
Page 393: ...LACP Commands 393 Oper Key 29 Partner System Priority 0 MAC Address 000000 000000 Oper Key 14 ...
Page 394: ...394 LACP Commands ...
Page 404: ...404 Link Dependency Commands ...
Page 432: ...432 LLDP Commands ...
Page 446: ...446 Port Monitor Commands 1 Enable 1 g10 1 g8 Rx Tx ...
Page 572: ...572 TACACS Commands ...
Page 610: ...610 VLAN Commands ...
Page 616: ...616 Voice VLAN Commands ...
Page 618: ...618 802 1x Commands 802 1x Option 81 radius server attribute 4 ...
Page 656: ...656 ARP Commands IP Address MAC Address Interface Type Age console ...
Page 822: ...822 IPv6 Routing Commands ...
Page 826: ...826 Loopback Interface Commands ...
Page 828: ...828 Multicast Commands show ip pimsm rphash show ip pimsm rp mapping ...
Page 854: ...854 Multicast Commands ...
Page 930: ...930 OSPF Commands ...
Page 933: ...OSPFv3 Commands 933 show ipv6 ospf virtual link show ipv6 ospf virtual link brief ...
Page 1004: ...1004 PIM SM Commands ...
Page 1014: ...1014 Router Discovery Protocol Commands ...
Page 1054: ...1054 Autoconfig Commands boot host dhcp boot host retry count show boot ...
Page 1058: ...1058 Autoconfig Commands ...
Page 1094: ...1094 Captive Portal Commands ...
Page 1110: ...1110 Clock Commands ...
Page 1130: ...1130 Configuration and Image File Commands ...
Page 1142: ...1142 Denial of Service Commands ...
Page 1178: ...1178 Power Over Ethernet Commands ...
Page 1220: ...1220 Serviceability Tracing Packet Commands ...
Page 1232: ...1232 Sflow Commands ...
Page 1262: ...1262 SNMP Commands ...
Page 1346: ...1346 System Management Commands 4 5 ...
Page 1350: ...1350 Telnet Server Commands ...
Page 1372: ...1372 Web Server Commands ...