Filtering - D-Link DES-3326SR User Manual

DES-3326SR Layer 3 Fast Ethernet Switch User's Guide
the packet to all ports, negating many of the benefits of having
a switch.
Static forwarding entries are not affected by the aging time.

Filtering

The switch uses a filtering database to segment the network
and control communication between segments. It can also filter
packets off the network for intrusion control. Static filtering
entries can be made by MAC Address or IP Address filtering.
Each port on the switch is a unique collision domain and the
switch filters (discards) packets whose destination lies on the
same port as where it originated. This keeps local packets from
disrupting communications on other parts of the network.
For intrusion control, whenever a switch encounters a packet
originating from or destined to a MAC address or an IP Address
entered into the filter table, the switch will discard the packet.
Some filtering is done automatically by the switch:
• Dynamic filtering – automatic learning and aging of MAC
addresses and their location on the network. Filtering
occurs to keep local traffic confined to its segment.
• Filtering done by the Spanning Tree Protocol, which can
filter packets based on topology, making sure that signal
loops don't occur.
• Filtering done for VLAN integrity. Packets from a member
of a VLAN (VLAN 2, for example) destined for a device on
another VLAN (VLAN 3) will be filtered.
Some filtering requires the manual entry of information into a
filtering table:
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