Cisco WS-C2960S-24PD-L Software Guide - Page 133

Configuring the DHCP Server

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Chapter 6 Configuring the System Changing IP Information Configuring the DHCP Server You should configure the DHCP servers with reserved leases that are bound to each switch by the switch hardware address. If the DHCP server does not support reserved leases, the switch can obtain different IP addresses and configuration files at different boot instances. You should configure the DHCP server with these lease options: • IP address of the client (required) • Subnet mask of the client (required) • DNS server IP address (required) • Router IP address (default gateway address to be used by the switch) (required) • TFTP server name (required) • Boot filename (the name of the configuration file that the client needs) (recommended) • Host name (optional) If you do not configure the DHCP server with the lease options described earlier, then it replies to client requests with only those parameters that have available values. If the IP address and subnet mask are not in the reply, the switch is not configured. If the DNS server IP address, router IP address, or TFTP server name are not found, the switch might broadcast TFTP requests. Unavailability of other lease options does not affect autoconfiguration. Note If the configuration file on the switch does not contain the IP address, the switch obtains its address, mask, gateway IP address, and host name from DHCP. If the service config global configuration command is specified in the configuration file, the switch receives the configuration file through TFTP requests. If the service config global configuration command and the IP address are both present in the configuration file, DHCP is not used, and the switch obtains the default configuration file by broadcasting TFTP requests. The DHCP server can be on the same or a different LAN as the switch. If it is on a different LAN, the switch must be able to access it through a relay device. The DHCP server can be running on a UNIX or Linux operating system; however, the Windows NT operating system is not supported in this release. For more information, see the "Configuring the Relay Device" section on page 6-7. You must also set up the TFTP server with the switch configuration files; for more information, see the next section. For CLI procedures, refer to the Cisco IOS Release 12.0 documentation on Cisco.com for additional information and CLI procedures. Configuring the TFTP Server The TFTP server must contain one or more configuration files in its base directory. The files can include the following: • The configuration file named in the DHCP reply (the actual switch configuration file) • The network-confg or the cisconet.cfg file (known as the default configuration files) • The router-confg or the ciscortr.cfg file (These files contain commands common to all switches. Normally, if the DHCP and TFTP servers are properly configured, these files are not accessed.) You must specify the TFTP server name in the DHCP server lease database. You must also specify the TFTP server name-to-IP-address mapping in the DNS server database. 78-6511-08 Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide 6-5

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6-5
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
78-6511-08
Chapter 6
Configuring the System
Changing IP Information
Configuring the DHCP Server
You should configure the DHCP servers with reserved leases that are bound to each switch by the switch
hardware address. If the DHCP server does not support reserved leases, the switch can obtain different
IP addresses and configuration files at different boot instances. You should configure the DHCP server
with these lease options:
IP address of the client (required)
Subnet mask of the client (required)
DNS server IP address (required)
Router IP address (default gateway address to be used by the switch) (required)
TFTP server name (required)
Boot filename (the name of the configuration file that the client needs) (recommended)
Host name (optional)
If you do not configure the DHCP server with the lease options described earlier, then it replies to client
requests with only those parameters that have available values. If the IP address and subnet mask are not
in the reply, the switch is not configured. If the DNS server IP address, router IP address, or TFTP server
name are not found, the switch might broadcast TFTP requests. Unavailability of other lease options does
not affect autoconfiguration.
Note
If the configuration file on the switch does not contain the IP address, the switch obtains its address,
mask, gateway IP address, and host name from DHCP. If the
service config
global configuration
command is specified in the configuration file, the switch receives the configuration file through TFTP
requests. If the
service config
global configuration command and the IP address are both present in the
configuration file, DHCP is not used, and the switch obtains the default configuration file by
broadcasting TFTP requests.
The DHCP server can be on the same or a different LAN as the switch. If it is on a different LAN, the
switch must be able to access it through a relay device. The DHCP server can be running on a UNIX or
Linux operating system; however, the Windows NT operating system is not supported in this release.
For more information, see the
“Configuring the Relay Device” section on page 6-7
. You must also set
up the TFTP server with the switch configuration files; for more information, see the next section.
For CLI procedures, refer to the Cisco IOS Release 12.0 documentation on Cisco.com for additional
information and CLI procedures.
Configuring the TFTP Server
The TFTP server must contain one or more configuration files in its base directory. The files can include
the following:
The configuration file named in the DHCP reply (the actual switch configuration file)
The network-confg or the cisconet.cfg file (known as the default configuration files)
The router-confg or the ciscortr.cfg file (These files contain commands common to all switches.
Normally, if the DHCP and TFTP servers are properly configured, these files are not accessed.)
You must specify the TFTP server name in the DHCP server lease database. You must also specify the
TFTP server name-to-IP-address mapping in the DNS server database.