How Automatic Configuration Works; Work Flow Of Automatic Configuration - 3Com 4500G Family Configuration Manual

name of the TFTP server from a DHCP response, the device can also resolve the domain name of
the TFTP server to the IP address of the TFTP server through the DNS server.
If the DHCP server, TFTP server, DNS server, and the device that performs automatic configuration are
not in the same segment, you need to configure DHCP relay on a device working as a gateway.

How Automatic Configuration Works

Basically, automatic configuration works in the following ways:
1) When a device starts up without loading any configuration file, the system sets the first active
interface (if an active Layer 2 Ethernet interface exists, this first interface is a virtual interface
corresponding with the default VLAN) as the DHCP client to request from the DHCP server for
parameters, such as an IP address and name of a TFTP server, IP address of a DNS server, and
the configuration file name.
2) After getting related parameters, the device will send a TFTP request to obtain the configuration file
from the specified TFTP server for system initialization. If the client cannot get such parameters, it
performs system initialization without loading any configuration file.
To implement auto-configuration, you need to configure some parameters on the DHCP server,
DNS server and TFTP server, but you do not need to perform any configuration on the device that
starts up without loading any configuration file. The configuration mode depends on the device
model; it is omitted here.
If you need to use the automatic configuration function, you are recommended to connect only the
interfaces needed in automatic configuration to the network.

Work Flow of Automatic Configuration

The work flow of automatic configuration is as shown in Figure 1-2.
1-2