PLANET WGSW-52040 - Manual (Page 246)

3. Function on changing dynamic ARP to static ARP
Command Explanation
Global Mode and Port Mode
ip arp-security convert Change dynamic ARP to static ARP.
28.3 Prevent ARP Spoofing Example
Switch
A B
C
Equipment Explanation
Equipment Configuration Quality
switch IP:192.168.2.4; mac: 00-00-00-00-00-04 1
A IP:192.168.2.1; mac: 00-00-00-00-00-01 1
B IP:192.168.1.2; mac: 00-00-00-00-00-02 1
C IP:192.168.2.3; mac: 00-00-00-00-00-03 some
There is a normal communication between B and C on above diagram. A wants switch to
forward packets sent by B to itself, so need switch sends the packets transfer from B to A.
firstly A sends ARP reply packet to switch, format is: 192.168.2.3, 00-00-00-00-00-01, mapping
its MAC address to C’s IP, so the switch changes IP address when it updates ARP list., then
data packet of 192.168.2.3 is transferred to 00-00-00-00-00-01 address (A MAC address).
In further, a transfers its received packets to C by modifying source address and destination
address, the mutual communicated data between B and C are received by A unconsciously.
Because the ARP list is update timely, another task for A is to continuously send ARP reply
packet, and refreshes switch ARP list.
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