Users Guide

DHCP and USB Auto-Configuration 581
Networking N1100-ON, N1500, N2000, and N2100-ON Series switches. If an
IP address has not been assigned, the switch issues requests for an IP address
assignment.
A network reachable DHCP server may return the following information:
• IP address and subnet mask to be assigned to the switch
• IP address of a default gateway, if needed for IP communication
After an IP address is assigned to the switch, if a hostname is not already
assigned, Auto Configuration issues a DNS request for the corresponding
hostname. This hostname is also displayed as the CLI prompt (as in response
to the hostname command).
Obtaining Other Dynamic Information
The following information is also processed and if returned by a BOOTP or
DHCP server:
• Name of a host configuration file (boot-file-name) to be downloaded from
the TFTP server.
The DHCP option 67 boot-file-name field can contain both a relative path
and file name.
• Name of an image configuration file (DHCP Option 125, sub-option 5).
• Identification of the TFTP server storing the file. The TFTP server can be
identified by name or by IP address as follows:
– hostname: DHCP option 66 or the sname field in the DHCP header)
– IP address: DHCP option 150 or the siaddr field in the DHCP header
• Domain Name Server - Option 6
• SYSLOG Server - Option 7
• Client Host Name - Option 12
• Domain Name - Option 15
• NTP Server - Option 42
When a DHCP OFFER identifies the TFTP server in multiple options, the
DHCP client selects from the options in the following order: sname, option
66, option 150, siaddr. If the TFTP server is identified by hostname, a
reachable DNS server is required to translate the name to an IP address.