
7-12
Configuring IP Addressing     
IP Configuration
Configuring IP Addressing
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 th e 
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 design ated 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:
j4108switch:\
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:
j4108switch:\
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:
j4108switch is a user-defined symbolic name to help you find the co rrect 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.
ht is the “hardware type”. For the S witch 4108GL, set this to ether (for Ethernet). 
This tag must precede the ha tag.
ha is the “hardware address”. Use the switch's (or VLAN's) 12-digit MAC address.
ip i s the IP address to be assigned to the switch (or VLAN ).
sm is the subnet mask of the subnet in which the switch (or VLAN) is installed.