D-Link DGS-3120-24PC - Page 822

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DGS-3120 Series Layer 2 Managed Stackable Gigabit Switch CLI Reference Guide
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Table 3 ARP Payload
When PC B replies to the query, the “Destination Address” in the Ethernet frame will be changed
to PC A’s MAC address. The “Source Address” will be changed to PC B’s MAC address (see
Table 4).
Table 4 Ethernet Frame Format
The switch will also examine the “Source Address” of the Ethernet frame and find that the address
is not in the Forwarding Table. The switch will learn PC B’s MAC and update its Forwarding Table.
How ARP Spoofing Attacks a Network
ARP spoofing,
also known as
ARP poisoning,
is a method to
attack an
Ethernet network
which may allow
an attacker to
sniff data frames
on a LAN,
modify the traffic,
or stop the traffic
altogether
(known as a
Denial of
Service – DoS
Figure 4