User's Manual

ISG50 User’s Guide 341
CHAPTER 21
IP/MAC Binding
21.1 IP/MAC Binding Overview
IP address to MAC address binding helps ensure that only the intended devices get to use privileged
IP addresses. The ISG50 uses DHCP to assign IP addresses and records to MAC address it assigned
each IP address. The ISG50 then checks incoming connection attempts against this list. A user
cannot manually assign another IP to his computer and use it to connect to the ISG50.
Suppose you configure access privileges for IP address 192.168.1.27 and use static DHCP to assign
it to Tim’s computer’s MAC address of 12:34:56:78:90:AB. IP/MAC binding drops traffic from any
computer trying to use IP address 192.168.1.27 with another MAC address.
Figure 225 IP/MAC Binding Example
21.1.1 What You Can Do in this Chapter
•Use the Summary and Edit screens (Section 21.2 on page 342) to bind IP addresses to MAC
addresses.
•Use the Exempt List screen (Section 21.3 on page 345) to configure ranges of IP addresses to
which the ISG50 does not apply IP/MAC binding.
21.1.2 What You Need to Know
DHCP
IP/MAC address bindings are based on the ISG50’s dynamic and static DHCP entries.
MAC: 12:34:56:78:90:AB
Bob
IP: 192.168.1.27
MAC: AB:CD:EF:12:34:56
Jim
IP: 192.168.1.27
ISG