Configuring IP Information
Configuring ARP
Cisco Small Business 300 Series Managed Switch Administration Guide 187
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STEP 3 Enter the Interface value.
• If the switch is in Layer 2 mode, select the VLAN that is to be DHCP Relay
enabled.
• If the switch is in Layer 3 mode, select whether the interface is for a port,
VLAN, or LAG.
STEP 4 Click Apply. A DHCP Relay interface is defined, and the switch is updated.
Configuring ARP
The switch maintains an ARP (Address Resolution Protocol) Table for all the known
devices that reside in its directly connected IP subnets. A directly connected IP
subnet is the subnet that a IPv4 interface of the switch is connected to. When the
switch needs to send/route a packet to a local device, it searches the ARP Table to
obtain the MAC address of the device. The ARP Table contains both static and
dynamic addresses. Static address are manually configured and do not age out.
The switch creates dynamic addresses from the ARP packets it receives. Dynamic
addresses age out after a configured time.
The ARP Table Page enables viewing dynamic ARP entries that the switch has
learned, changing the ARP entry aging time, clearing ARP entries, and adding or
deleting static ARP entries.
NOTE In Layer 2 mode, the IP, MAC address mapping information in ARP Table is used by
the switch to forward the traffic originated by the switch. In Layer 3 mode, the
mapping information is used for Layer 3 routing as well as to forward the generated
traffic.
To define the ARP tables:
STEP 1 Click IP Configuration > ARP. The ARP Table Page opens.
STEP 2 Enter the parameters.
• ARP Entry Age Out—Enter the number of seconds that dynamic addresses
can remain in the ARP table. A dynamic address ages out after the time it is
in the table exceeds the ARP Entry Age Out time. When a dynamic address
ages out, it is deleted from the table, and needs to be relearned to be
entered into the table again.