Using Dhcp To Obtain An Ip Address And Other Configuration Information - H3C S5500-HI Series Fundamentals Configuration Manual

Figure 47 Automatic configuration work flow
Using DHCP to obtain an IP address and other configuration
information
Address acquisition process
As previously mentioned, a device sets the first up interface as the DHCP client during startup. The DHCP
client broadcasts a DHCP request, where the Option 55 field specifies the information that the client
wants to obtain from the DHCP server such as the configuration file name, domain name and IP address
of the TFTP server, and DNS server IP address.
After receiving the DHCP response from the DHCP server, the device obtains the IP address and resolves
the following fields in the DHCP response:
Option 67 or the file field—Obtains the configuration file name. The device resolves Option 67 first.
•
If Option 67 contains the configuration file name, the device does not resolve the file field. If not, the
device resolves the file field.
Option 66—Obtains the TFTP server domain name
•
Option 150—Obtains the TFTP server IP address
•
Option 6—Obtains the DNS server IP address.
•
If no response is received from the DHCP server, the device removes the temporary configuration and
starts up with the factory defaults.
The temporary configuration contains two parts: the configuration made on the interface through which
automatic configuration is performed, and the ip host command in the host name file. The temporary
configuration is removed by executing the corresponding undo commands.
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