ZyXEL Communications MES-2110, User Manual

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Chapter 17 IP Source Guard
MES-2110 User’s Guide
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17.4 The ARP Inspection Screen
Use ARP inspection to filter unauthorized ARP frames on the network. This can
prevent many kinds of man-in-the-middle attacks, such as the one in the following
example.
Figure 65 Example: Man-in-the-middle Attack
In this example, computer B tries to establish a connection with computer A .
Computer X is in the same broadcast domain as computer A and intercepts the
ARP request for computer A . Then, computer X does the following things:
• It pretends to be computer A and responds to computer B .
• It pretends to be computer B and sends a message to computer A .
As a result, all the communication between computer A and computer B passes
through computer X . Computer X can read and alter the information passed
between them.
No. This field displays a sequential number for each binding.
Port This field displays the port number in the binding.
VLAN ID This field displays the source VLAN ID in the binding.
MAC Address This field displays the source MAC address in the binding.
IP Address This field displays the IP address assigned to the MAC address in
the binding.
Delete Click this to delete a static binding rule.
Lease Time
(DD:HH:MM) This field displays how many days, hours and minutes the binding
is valid; for example,
02:03:04 means the binding is still valid for
2 days, 3 hours and 4 minutes.
Table 50 Configuration > DHCP Snooping > DHCP Binding Table
LABEL DESCRIPTION
A
X
B