D-Link DES-3326 User Manual - page 51
DES-3326 Layer 3 Fast Ethernet Switch User’s Guide
Switch Management and Operating Concepts
37
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:
•
MAC address filtering – the manual entry of specific
MAC addresses to be filtered from the network. Packets
sent from one manually entered MAC address can be
filtered from the network. The entry may be specified
as either a source, a destination, or both.
•
IP address filtering – the manual entry of specific IP
addresses to be filtered from the network (switch must
be in IP Routing mode). Packets sent from one
manually entered IP address to another can be filtered
from the network. The entry may specified as either a