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Lantronix
SM24TBT2DPA and SM24TBT2DPB Web User Guide
Appendix A – DHCP Per Port
You can configure DHCP Per Port via the CLI and Web UI as described below. The DHCP Per Port factory
default mode is Disabled. See the
SM24TBT2DPx CLI Reference
for CLI mode operation.
Note
: do not
operate DHCP Per Port and DHCP Pool per VLAN at the same time. If you configure entries for DHCP
Pool per VLAN and then enable DHCP per Port, the configured DHCP pool will be deleted.
Configure DHCP Per Port
The switch’s DHCP server assigns IP addresses. Clients get IP addresses in sequence and the switch
assigns IP addresses on a per-port basis starting from the configured IP range. For example, if the IP
address range is configured as 192.168.10.20 - 192.168.10.37 with one DHCP device connected to port 1,
the client will always get IP address 192.168.10.20, then port 3 is always distributed IP address
192.168.10.22, even if port 2 is an empty port (because port 2 is always distributed IP address
192.168.10.21).
The switch does not allow a DHCP per Port pool to include the switch’s address.
IP address assigned range and VLAN 1 should stay in the same subnet mask.
The configurable IP address range is allowed to configure over 18 IP addresses, but the switch always
assigns one IP address per port connecting device.
The DHCP Per Port function is only supported on VLAN 1.
When the DHCP Per Port function is enabled, the switch software will automatically create the related
DHCP pool named “DHCP_Per_Port”.
Once the DHCP Per Port function is enabled on one switch, IPv4 DHCP client at VLAN1 mode (DMS
DHCP mode), DHCP server mode are all limited to be enabled at the same time (an error message
displays if attempted).
If the DHCP server pool has been configured, once you enable the DHCP Per Port function, then that
DHCP server pool configuration will be overwritten.
Only for VLAN 1, clients issued DHCP packets will not be broadcast/forwarded to other ports. DHCP
packets in others VLANs will be broadcast/forwarded to other ports.
The DHCP Per Port function allows the switch to connect only one DHCP client device.
DHCP-Per-Port is configured entirely on the
Switch
>
Configuration
>
System
>
IP
page, IP Interfaces
window.
The feature is enabled here and an IP range (pool) is entered. The “automatic” results of this action can be
displayed in:
•
Switch
>
Configuration
>
System
>
DHCP
>
Server
>
Mode
(Global Mode – Enabled, VLAN Mode
- VLAN 1 created)
•
Switch
>
Configuration
>
System
>
DHCP
>
Excluded
(Excluded range created based on range
entered)
•
Switch
>
Configuration
>
System
>
DHCP
>
Pool
(Pool “DHCP_Per_Port” created based on range
entered)
Actual DHCP operation is monitored as normal under
System
>
Monitor
>
DHCP
.
The DHCP Per Port pages and parameters are described below.