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Catalyst 3750-X and 3560-X Switch Software Configuration Guide
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Chapter 3 Assigning the Switch IP Address and Default Gateway Assigning Switch Information
DHCP Server Configuration Guidelines
Follow these guidelines if you are configuring a device as a DHCP server:
• You should configure the DHCP server with reserved leases that are bound to each switch by the
switch hardware address.
• If you want the switch to receive IP address information, you must configure the DHCP server with
these lease options:
–
IP address of the client (required)
–
Subnet mask of the client (required)
–
DNS server IP address (optional)
–
Router IP address (default gateway address to be used by the switch) (required)
• If you want the switch to receive the configuration file from a TFTP server, you must configure the
DHCP server with these lease options:
–
TFTP server name (required)
–
Boot filename (the name of the configuration file that the client needs) (recommended)
–
Hostname (optional)
• Depending on the settings of the DHCP server, the switch can receive IP address information, the
configuration file, or both.
• If you do not configure the DHCP server with the lease options described previously, it replies to
client requests with only those parameters that are configured. If the IP address and the subnet mask
are not in the reply, the switch is not configured. If the router IP address or the TFTP server name
are not found, the switch might send broadcast, instead of unicast, TFTP requests. Unavailability of
other lease options does not affect autoconfiguration.
• The switch can act as a DHCP server. By default, the Cisco IOS DHCP server and relay agent
features are enabled on your switch but are not configured. These features are not operational. If
your DHCP server is a Cisco device, for additional information about configuring DHCP, see the
“Configuring DHCP” section of the “IP Addressing and Services” section of the Cisco IOS IP
Configuration Guide.
Configuring the TFTP Server
Based on the DHCP server configuration, the switch attempts to download one or more configuration
files from the TFTP server. If you configured the DHCP server to respond to the switch with all the
options required for IP connectivity to the TFTP server, and if you configured the DHCP server with a
TFTP server name, address, and configuration filename, the switch attempts to download the specified
configuration file from the specified TFTP server.
If you did not specify the configuration filename, the TFTP server, or if the configuration file could not
be downloaded, the switch attempts to download a configuration file by using various combinations of
filenames and TFTP server addresses. The files include the specified configuration filename (if any) and
these files: network-config, cisconet.cfg, hostname.config, or hostname.cfg, where hostname is the
switch’s current hostname. The TFTP server addresses used include the specified TFTP server address
(if any) and the broadcast address (255.255.255.255).