Displaying Address Table Entries; Managing The Arp Table - Cisco 3020 - Catalyst Blade Switch Configuration Manual

Managing the ARP Table

This example shows how to enable unicast MAC address filtering and to configure the switch to drop
packets that have a source or destination address of c2f3.220a.12f4. When a packet is received in
VLAN 4 with this MAC address as its source or destination, the packet is dropped:
Switch(config)# mac

Displaying Address Table Entries

You can display the MAC address table by using one or more of the privileged EXEC commands
described in
Table 5-4 Commands for Displaying the MAC Address Table
Command
show ip igmp snooping groups
show mac address-table address
show mac address-table aging-time
show mac address-table count
show mac address-table dynamic
show mac address-table interface
show mac address-table notification
show mac address-table static
show mac address-table vlan
Managing the ARP Table
To communicate with a device (over Ethernet, for example), the software first must learn the 48-bit MAC
address or the local data link address of that device. The process of learning the local data link address
from an IP address is called address resolution.
The Address Resolution Protocol (ARP) associates a host IP address with the corresponding media or
MAC addresses and the VLAN ID. Using an IP address, ARP finds the associated MAC address. When
a MAC address is found, the IP-MAC address association is stored in an ARP cache for rapid retrieval.
Then the IP datagram is encapsulated in a link-layer frame and sent over the network. Encapsulation of
IP datagrams and ARP requests and replies on IEEE 802 networks other than Ethernet is specified by
the Subnetwork Access Protocol (SNAP). By default, standard Ethernet-style ARP encapsulation
(represented by the arpa keyword) is enabled on the IP interface.
ARP entries added manually to the table do not age and must be manually removed.
For CLI procedures, see the Cisco IOS Release 12.2 documentation on Cisco.com.
Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
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a
ddress-table static c2f3.220a.12f4 vlan 4 drop
Table 5-4:
Description
Displays the Layer 2 multicast entries for all VLANs or the specified VLAN.
Displays MAC address table information for the specified MAC address.
Displays the aging time in all VLANs or the specified VLAN.
Displays the number of addresses present in all VLANs or the specified VLAN.
Displays only dynamic MAC address table entries.
Displays the MAC address table information for the specified interface.
Displays the MAC notification parameters and history table.
Displays only static MAC address table entries.
Displays the MAC address table information for the specified VLAN.
Chapter 5 Administering the Switch
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