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Configuring IP Addressing
IP Preserve: Retaining VLAN-1 IP Addressing Across Configuration File Downloads
connectivity to the TFTP file server specified in the reply, that the config-
uration file is correctly named, and that the configuration file exists in the
TFTP directory.)
IP Preserve: Retaining VLAN-1 IP
Addressing Across Configuration File
Downloads
IP Preserve enables you to copy a configuration file to multiple switches that
use the same operating-system software while retaining the individual IP
address and subnet mask on VLAN 1 in each switch, and the Gateway IP
address assigned to the switch. This enables you to distribute the same
configuration file to multiple switches without overwriting their individual IP
addresses.
Operating Rules for IP Preserve
When ip preserve is entered as the last line in a configuration file stored on a
TFTP server:
■ If the switch’s current IP address for VLAN 1 was not configured by DHCP/
Bootp, IP Preserve retains the switch’s current IP address, subnet mask,
and IP gateway address when the switch downloads the file and reboots.
The switch adopts all other configuration parameters in the configuration
file into the startup-config file.
■ If the switch’s current IP addressing for VLAN 1 is from a DHCP server,
IP Preserve is suspended. In this case, whatever IP addressing the config-
uration file specifies is implemented when the switch downloads the file
and reboots. If the file includes DHCP/Bootp as the IP addressing source
for VLAN 1, the switch will configure itself accordingly and use DHCP/
Bootp. If instead, the file includes a dedicated IP address and subnet mask
for VLAN 1 and a specific gateway IP address, then the switch will
implement these settings in the startup-config file.
■ The ip preserve statement does not appear in show config listings. To verify
IP Preserve in a configuration file, open the file in a text editor and view
the last line. For an example of implementing IP Preserve in a configura-
tion file, see figure
8-6, below.
To set up IP Preserve, enter the ip preserve statement at the end of a configu-
ration file. (Note that you do not execute IP Preserve by entering a command
from the CLI).
8-16