Dhcp Snooping Overview; Function Of Dhcp Snooping - 3Com MSR 50 Series Configuration Manual

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DHCP Snooping
Overview
Function of DHCP
Snooping
DHCP S
When configuring DHCP snooping, go to these sections for information you are
interested in:
"DHCP Snooping Overview" on page 601
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"Configuring DHCP Snooping Basic Functions" on page 602
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"Displaying and Maintaining DHCP Snooping" on page 602
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"DHCP Snooping Configuration Example" on page 602
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The DHCP snooping is supported only on Layer 2 Ethernet interfaces.
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DHCP Snooping supports no link aggregation. If a Layer 2 Ethernet interface is
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added into an aggregation group, DHCP Snooping configuration on it will not
take effect. When the interface is removed from the group, DHCP Snooping
can take effect.
The DHCP snooping enabled device does not work if it is between the DHCP
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relay agent and DHCP server, and it can work when it is between the DHCP
client and relay agent or between the DHCP client and server.
The DHCP Snooping enabled device cannot be a DHCP server or DHCP relay
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agent.
You are not recommended to enable the DHCP client, BOOTP client, and DHCP
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Snooping on the same device. Otherwise, DHCP Snooping entries may fail to
be generated, or the BOOTP client/DHCP client may fail to obtain an IP address.
c
CAUTION: Only H3C MSR series routers equipped with 16-port or 24-port layer 2
interface cards support the DHCP Snooping function.
As a DHCP security feature, DHCP snooping can implement the following:
Recording IP-to-MAC mappings of DHCP clients
For security sake, a network administrator needs to record the mapping between a
client's IP address obtained from the DHCP server and the client's MAC address.
DHCP snooping can meet the need.
DHCP snooping records clients' MAC and IP addresses by reading their
DHCP-REQUEST and DHCP-ACK messages from trusted ports. The network
administrator can check out which IP addresses are assigned to the DHCP clients
with the display dhcp-snooping command.
C
NOOPING ONFIGURATION