3Com E4500-24, Руководство по настройке CLI, Страница: 489 / 848

6-2
Configuring a DHCP/BOOTP Client
Follow these steps to configure a DHCP/BOOTP client:
To do… Use the command… Remarks
Enter system view system-view —
Enter VLAN interface view
interface vlan-interface
vlan-id
—
Configure the VLAN interface
to obtain IP address through
DHCP or BOOTP
ip address { bootp-alloc |
dhcp-alloc }
Required
By default, no IP address is
configured for the VLAN
interface.
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Currently, an S4500 Ethernet switch functioning as the DHCP client can use an IP address for 24
days at most. That is, the DHCP client can obtain an address lease for no more than 24 days even
though the DHCP server offers a longer lease period.
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An S4500 Ethernet switch functioning as a DHCP client supports default route creation. That is, the
DHCP client creates a default route with the next hop being the gateway assigned by the DHCP
server. To view detailed information about the default route, run the display ip routing-table
command on the switch.
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If a switch belongs to an XRN fabric, you need to enable the UDP Helper function on the switch
before configuring its VLAN interfaces to obtain IP addresses through DHCP.
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An S4500 Ethernet switch functioning as a DHCP client supports default route creation. That is, the
DHCP client creates a default route with the next hop being the gateway assigned by the DHCP
server. To view detailed information about the default route, run the display ip routing-table
command on the switch.
To improve security and avoid malicious attack to the unused SOCKETs, S4500 Ethernet switches
provide the following functions:
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UDP 67 and UDP 68 ports used by DHCP are enabled only when DHCP is enabled.
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UDP 67 and UDP 68 ports are disabled when DHCP is disabled.
The specific implementation is:
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Using the ip address dhcp-alloc command enables the DHCP client, and UDP port 68.
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Using the undo ip address dhcp-alloc command disables the DHCP client, and UDP port 68.