3com 5500 User Manual

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You need to specify the port connected to the authorized DHCP server as a 
trusted port to ensure that DHCP clients can obtain valid IP addresses. The 
trusted port and the ports connected to the DHCP clients must be in the same 
VLAN.

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To enable DHCP snooping on a Switch 5500 that belongs to an XRN fabric, you 
need to set the fabric ports on all devices in the fabric to DHCP snooping 
trusted ports to ensure that the clients connected to each device can obtain IP 
addresses.

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You are not recommended to configure both the DHCP client/BOOTP client and 
DHCP snooping on the same device; otherwise, the switch may fail to record 
DHCP snooping entries.

DHCP accounting allows a DHCP server to notify the RADIUS server of the 
start/end of accounting when it assigns/releases a lease. The cooperation of the 
DHCP server and RADIUS server implements the network accounting function and 
ensures network security at the same time.

Figure 57   Network diagram for DHCP accounting configuration

 

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The DHCP server connects to a DHCP client and a RADIUS server through 
Ethernet 1/0/1 and Ethernet 1/0/2 respectively.

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Ethernet 1/0/1 belongs to VLAN 2; Ethernet 1/0/2 belongs to VLAN 3.

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The IP address of VLAN-interface 2 is 10.1.1.1/24, that of VLAN-interface 3 is 
10.1.2.1/24, and that of the RADIUS server is 10.1.2.2/24.

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DHCP accounting is enabled on the DHCP server.

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The global DHCP address pool belongs to the network segment 10.1.1.0. The 
DHCP server operates as a RADIUS client and adopts AAA for authentication.

# Create VLAN 2.

[3Com] vlan 2

[3Com-vlan2] quit 

# Create VLAN 3.

[3Com] vlan 3

[3Com-vlan3] quit 

IP:10.1.2.2/24

Vlan -int2

10 .1 .1.1/24

Vlan -int3
10.1.2.1 /24

Eth1/0/1

Eth1/0/2

Switch 5500

Release V03.02.04 

All versions 

Switch 5500G

Release V03.02.04 

All versions