Obtaining Configuration Files - Cisco WS-C2955T-12 Software Manual

Changing IP Information

Obtaining Configuration Files

Depending on the availability of the IP address and the configuration filename in the DHCP reserved
lease, the switch obtains its configuration information in these ways:
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Note
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
6-8
The IP address and the configuration filename is reserved for the switch and provided in the DHCP
reply (one-file read method).
The switch receives its IP address, subnet mask, and configuration filename from the DHCP server.
It also receives a DNS server IP address and a TFTP server name. The switch sends a DNS request
to the DNS server, specifying the TFTP server name, to obtain the TFTP server address. Then the
switch sends a unicast message to the TFTP server to retrieve the named configuration file from the
base directory of the server, and upon receipt, completes its boot-up process.
Only the configuration filename is reserved for the switch. The IP address is dynamically allocated
to the switch by the DHCP server (one-file read method).
The switch follows the same configuration process described above.
Only the IP address is reserved for the switch and provided in the DHCP reply. The configuration
filename is not provided (two-file read method).
The switch receives its IP address and subnet mask from the DHCP server. It also receives a DNS
server IP address and a TFTP server name. The switch sends a DNS request to the DNS server,
specifying the TFTP server name, to obtain the TFTP server address.
The switch sends a unicast message to the TFTP server to retrieve the network-confg or cisconet.cfg
default configuration file. (If the network-confg file cannot be read, the switch reads the cisconet.cfg
file.)
The default configuration file contains the host names-to-IP-address mapping for the switch. The
switch fills its host table with the information in the file and obtains its host name. If the host name
is not found in the file, the switch uses the host name in the DHCP reply. If the host name is not
specified in the DHCP reply, the switch uses the default "Switch" as its host name.
After obtaining its host name from the default configuration file or the DHCP reply, the switch reads
the configuration file that has the same name as its host name (hostname-confg or hostname.cfg,
depending on whether network-confg or cisconet.cfg was read earlier) from the TFTP server. If the
cisconet.cfg file is read, the filename of the host is truncated to eight characters.
If the switch cannot read the network-confg, cisconet.cfg, or the host-name file, it reads the
router-confg file. If the switch cannot read the router-confg file, it reads the ciscortr.cfg file.
The switch broadcasts TFTP server requests if the TFTP server name is not obtained from the
DHCP replies, if all attempts to read the configuration file through unicast transmissions fail, or
if the TFTP server name cannot be resolved to an IP address.
Chapter 6 Configuring the System
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