H3C Technologies H3C S12500 Series Switches - Manual (Page 52)

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• If you use the static-bind ip-address, static-bind mac-address, or static-bind client-identifier
command multiple times in the DHCP address pool, the most recent configuration takes effect.
• The IP address of the static binding cannot be an interface address of the DHCP server. Otherwise,
an IP address conflict might occur and the bound client cannot obtain an IP address correctly.
• The ID of the static binding must be identical to the ID displayed by using the display dhcp client
verbose command on the client. Otherwise, the client cannot obtain an IP address.
• The specified lease duration takes effect for the static binding, but the lease duration displayed by
the display dhcp server ip-in-use all command is still Unlimited.
• When the switch serves as a DHCP client, you must configure the static binding of the DHCP client's
ID to IP address on the DHCP server. Otherwise, the DHCP client cannot obtain a static IP address.
• If the interfaces on a DHCP client share the same MAC address, you must specify the client ID,
rather than MAC address, in a static binding to identify the requesting interface. Otherwise, the
client might fail to obtain an IP address.
To configure a static binding in a common DHCP address pool:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter common address pool
view.
dhcp server ip-pool pool-name N/A
3. Bind IP addresses statically. static-bind ip-address ip-address
[ mask-length | mask mask ]
No IP addresses are statically
bound by default.
4. Bind MAC addresses or IDs
statically.
• Specify the MAC address:
static-bind mac-address
mac-address
• Specify the ID:
static-bind client-identifier
client-identifier
Use either command.
Neither is bound statically by
default.
5. Specify the lease duration
for the IP address.
expired { day day [ hour hour [ minute
minute [ second second ] ] ] |
unlimited }
Optional.
By default, the lease duration of
the IP address is unlimited.
Configuring dynamic address allocation
For dynamic address allocation, you must configure a DHCP address pool, specify one and only one
address range for the pool, and specify the lease duration. A DHCP address pool can have only one
lease duration.
To avoid address conflicts, configure the DHCP server to exclude IP addresses used by the gateway or
FTP server from dynamic allocation.
Follow these guidelines when you configure dynamic address allocation:
• In common address pool view, if you use the network or network ip range command multiple times,
the most recent configuration takes effect.
• After you exclude IP addresses from automatic allocation using the dhcp server forbidden-ip
command, neither a common address pool nor an extended address pool can assign these IP
addresses through dynamic address allocation.
• You can exclude multiple IP address ranges from allocation.
To configure the dynamic address allocation: