Setting DHCP Auto Configuration
Dynamic Host Configuration Protocol (DHCP) provides a means of passing configuration information (including the IP address of a TFTP server and a configuration file name) to hosts on a TCP/IP network. By default, the switch is enabled as a DHCP client.
DHCP Auto Configuration
When the IP address is allocated or renewed, such as during a reboot or upon an explicit DHCP renewal request and if the switch and the server are configured to do so, the switch transfers a configuration file from the TFTP server identified to the switch by DHCP. This process is known as auto configuration.
NOTE If you enable DHCP Auto Configuration on a switch with DHCP disabled, you must enable the DHCP by using the procedure is described in the DHCP Relay section.
The DHCP Auto Configuration page configures the switch to receive DHCP information pointing to a TFTP server for auto configuration purposes or manual configuration of the TFTP server and configuration file in the event that the information is not provided in a DHCP message.
Note the following limitations regarding the DHCP auto-update process:
- A configuration file that is placed on the TFTP server must match the form and format requirements of a supported configuration file. The form and format of the file are checked, but the validity of the configuration parameters is not checked prior to loading it to the Startup Configuration.
- To make sure the configuration of devices functions as intended and due to allocation of different IP addresses with each DHCP renew cycle, IP addresses must be bound to MAC addresses in the DHCP server table. This ensures that each device has its own reserved IP address and other relevant information.
To configure DHCP server auto configuration:
- Click Administration > File Management > DHCP Auto Configuration. The DHCP Auto Configuration page opens.
- Enter the values.
- Auto Configuration Via DHCP--Select this field to enable the automatic transfer of a configuration file from a TFTP server to the Startup Configuration on the switch.
- Server Definition--Select By IP Address or By name.
- Backup TFTP Server IP Address/Name--Enter the IP address or the name of the TFTP server to be used if no TFTP server IP address was specified in the DHCP message.
- Backup Configuration File--Enter the path and file name of the file to be used when no configuration file name was specified in the DHCP message.
The window displays the following:
- Last Auto Configuration TFTP Server IP Address--Displays the IP address of the TFTP server last used to perform auto configuration.
- Last Auto Configuration File Name--Displays the last file name used by the switch in auto configuration.
The Last Auto Configuration TFTP Server IP Address and the Last Auto Configuration File Name are compared with the information received from a DHCP server in conjunction with receiving a configuration IP address for the switch. In the event that these values do not match, the switch transfers the configuration file from the TFTP server identified by the DHCP server into the Startup Configuration file, and initiates a reboot. If the values match, no action is taken.
- Click Apply. The DHCP Auto Configuration feature is updated.