3-6
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 3 Assigning the Switch IP Address and Default Gateway
Assigning Switch Information
Note For procedures to configure the switch as a DHCP server, see the “Configuring DHCP Autoconfiguration
(Only Configuration File)” section on page 3-11 and the “Configuring DHCP” section of the “IP
Addressing and Services” section of the Cisco IOS IP Configuration Guide, Release 12.2 at this URL:
http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfdhcp.html
After you install the switch in your network, the auto-image update feature starts. The downloaded
configuration file is saved in the running configuration of the switch, and the new image is downloaded
and installed on the switch. When you reboot the switch, the configuration is stored in the saved
configuration on the switch.

Limitations and Restrictions

These are the limitations:
• The DHCP-based autoconfiguration with a saved configuration process stops if there is not at least
one Layer 3 interface in an up state without an assigned IP address in the network.
• Unless you configure a timeout, the DHCP-based autoconfiguration with a saved configuration
feature tries indefinitely to download an IP address.
• The auto-install process stops if a configuration file cannot be downloaded or it the configuration
file is corrupted.
Note The configuration file that is downloaded from TFTP is merged with the existing configuration in the
running configuration but is not saved in the NVRAM unless you enter the write memory or
copy running-configuration startup-configuration privileged EXEC command. Note that if the
downloaded configuration is saved to the startup configuration, the feature is not triggered during
subsequent system restarts.
Configuring DHCP-Based Autoconfiguration
These sections contain this configuration information:
• DHCP Server Configuration Guidelines, page 3-7
• Configuring the TFTP Server, page 3-7
• Configuring the DNS, page 3-8
• Configuring the Relay Device, page 3-8
• Obtaining Configuration Files, page 3-9
• Example Configuration, page 3-10
Note 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, Release 12.2 at this URL:
http://www.cisco.com/en/US/docs/ios/12_2/ip/configuration/guide/1cfdhcp.html