Dhcp snooping, Dhcp s – Microsens MS453490M Management Guide User Manual

Page 342

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| Security Measures

DHCP Snooping

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NTERFACE

To display the binding table for IP Source Guard:

1.

Click Security, IP Source Guard, Dynamic Binding.

2.

Mark the search criteria, and enter the required values.

3.

Click Query

Figure 196: Showing the IP Source Guard Binding Table

DHCP S

NOOPING

The addresses assigned to DHCP clients on insecure ports can be carefully

controlled using the dynamic bindings registered with DHCP Snooping (or

using the static bindings configured with IP Source Guard). DHCP snooping

allows a switch to protect a network from rogue DHCP servers or other

devices which send port-related information to a DHCP server. This

information can be useful in tracking an IP address back to a physical port.

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SAGE

DHCP Snooping Process

Network traffic may be disrupted when malicious DHCP messages are

received from an outside source. DHCP snooping is used to filter DHCP

messages received on a non-secure interface from outside the network

or fire wall. When DHCP snooping is enabled globally and enabled on a

VLAN interface, DHCP messages received on an untrusted interface

from a device not listed in the DHCP snooping table will be dropped.

Table entries are only learned for trusted interfaces. An entry is added

or removed dynamically to the DHCP snooping table when a client

receives or releases an IP address from a DHCP server. Each entry

includes a MAC address, IP address, lease time, VLAN identifier, and

port identifier.

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