Configuring the Switch

IP Configuration

DHCP Operation

A significant difference between a DHCP configuration and a Bootp configuration is that an IP address assignment from a DHCP server is automatic, requiring no configuration of the DHCP server. Using that automatic feature, though, the address is temporarily leased. Periodically the switch is required to renew its lease of the IP configuration.

As a result, the IP addressing provided by the server may be different each time the switch reboots or renews its configuration from the server. This may cause a problem for you if you access the switch through the web browser interface, since the IP address is used as the browser URL.

However, you can fix the address assignment for the switch by doing either of the following:

■Using the switch’s MAC address as an identifier, configure the server with a “Reservation” so that it will always assign the same IP address to the switch. (For MAC address information, refer to appendix B, “MAC Address Management”.)

■Configure the server to issue an “infinite” lease.

For more information on either of these procedures, refer to the documentation provided with the DHCP server.

Bootp Operation

When a Bootp server receives a request it searches its Bootp database for a record entry that matches the MAC address in the Bootp request from the switch. If a match is found, the configuration data in the associated database record is returned to the switch. For most Unix systems, the Bootp database is contained in the /etc/bootptab file. In contrast to DHCP operation, Bootp configurations are always the same for each receiving device. That is, the Bootp server replies to a request with a configuration previously stored in the server and designated for the requesting device.

Bootp Database Record Entries. A minimal entry in the Bootp table file /etc/bootptab to provide an IP address and subnet mask to the switch would be similar to this entry:

j3299switch:\ht=ether:\ha=0060b0123456:\ip=11.22.33.44:\sm=255.255.248.0:\vm=rfc1048

Switch the Configuring

6-11