Basic Operation Guide 2014/02

provided by the server may be different each time the switch reboots or renews its configuration
from the server. However, you can fix the address assignment for the switch by doing either of the
following:
• Configure the server to issue an “infinite” lease.
• 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,
See Appendix D, “MAC Address Management”.)
For more information on either of these procedures, See 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 many
Unix systems, the Bootp database is contained in the /etc/bootptab file. In contrast to DHCP
operation, Bootp configurations are always the same for a specific 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 update
an IP address and subnet mask to the switch or a VLAN configured in the switch would be similar
to this entry:
8212switch:\
ht=ether:\
ha=0030c1123456:\
ip=10.66.77.88:\
sm=255.255.248.0:\
gw=10.66.77.1:\
hn:\
vm=rfc1048
An entry in the Bootp table file /etc/bootptab to tell the switch or VLAN where to obtain a
configuration file download would be similar to this entry:
8212switch:\
ht=ether:\
ha=0030c1123456:\
ip=10.66.77.88:\
sm=255.255.248.0:\
gw=10.66.77.1:\
lg=10.22.33.44:\
T144="switch.cfg":\
vm=rfc1048
where:
is a user-defined symbolic name to help you find the correct section of the bootptab file. If you have multiple
switches that will be using Bootp to get their IP configuration, you should use a unique symbolic name for
each switch.
8212switch
is the "hardware type". For the switches covered in this guide, enter ether (for Ethernet). This tag must
precede the ha tag.
ht
is the "hardware address". Use the switch's (or VLAN's) 12-digit MAC address.ha
is the IP address to be assigned to the switch (or VLAN).ip
is the subnet mask of the subnet in which the switch (or VLAN) is installed.sm
is the IP address of the default gateway.gw
TFTP server address (source of final configuration file)lg
110 Configuring IP Addressing