Dell SmartFabric OS10 User Guide Release 10.5.3

Dynamic Host Configuration Protocol

Dynamic Host Configuration Protocol (DHCP) is an application layer protocol that dynamically assigns IP addresses and other configuration parameters to network end-stations, also known as hosts, based on configuration policies network administrators determine.

DHCP server

Network device offering configuration parameters to the client.

DHCP client

Network device requesting configuration parameters from the server.

Relay agent

Intermediary network device that passes DHCP messages between the client and the server when the server is not on the same subnet as the host.

If you attempt to enable (start) the DHCP server with an incorrect configuration, you must re-enable the DHCP server after you enter the correct configuration.

OS10# show running-configuration ip dhcp
!
ip dhcp server
no disable
!
pool netdhcp1
lease infinite
network 35.1.1.0/24
!
pool netdhcp2
network 40.1.1.0/24
OS10# show ip interface brief
Interface Name IP-Address OK Method Status
Protocol
======================================================================================
===
Ethernet 1/1/1 unassigned YES unset up
up
Ethernet 1/1/2 unassigned YES unset up
up
…
Ethernet 1/1/32 unassigned NO unset up down
…

To resolve this issue, you must:

1. Configure a matching interface for pool netdhcp2-40.1.1.1/24 matches 40.1.1.0/24.

   OS10(config)# interface ethernet 1/1/2
   OS10(conf-if-eth1/1/2)# no shutdown
   OS10(conf-if-eth1/1/2)# no switchport
   OS10(conf-if-eth1/1/2)# ip address 40.1.1.1/24
   

2. Run the show ip interface brief command to verify if an IP address is assigned to ethernet 1/1/2 port.

   OS10# show ip interface brief
   Interface Name IP-Address OK Method Status
   Protocol
   ====================================================================================
   =====
   Ethernet 1/1/1 unassigned YES unset up
   up
   Ethernet 1/1/2 40.1.1.1/24 YES manual up
   up
   …
   

3. Re-enable the DHCP server because it failed to start initially.

   OS10# configure terminal
   OS10(config)# ip dhcp server
   OS10(config-dhcp)# disable
   OS10(config-dhcp)# no disable
   OS10(config-dhcp)#
   

Configuration notes

All Dell PowerSwitches except S4200-Series, S5200 Series, and Z9332F-ON:

• Before you configure a DHCP address pool, you must configure a DHCP server interface with an IP address in the range that is used in the DHCP address pool. If you configure the DHCP address pool first, and then configure a DHCP server interface, to enable automatic DHCP address allocation, you must restart the DHCP service using the disable and no disable commands. Select one of the choices for successfully configuring a DHCP address pool:
  • Configure manual binding for a host/hardware MAC address in the IP address range that is used for the DHCP pool.
  • Configure a network statement with a valid IP address range.
• DHCP client is enabled by default on the management interface. The management interface automatically tries to obtain an IP address from a DHCP server. To manually configure an IP address on the management port, disable the DHCP client using the no ip address dhcp command in Interface mode
• The DHCP server does not start unless at least one interface matches one of the configured network pools. An interface matches a network pool when you include the IP address in the subnet that is defined for that network pool. For example, an interface with IP address 10.1.1.1/24 matches a pool that is configured with network 10.1.1.0/24.