Lantronix XPort - Manual (Page 66)

IP Addresses
Alternative Ways to Assign an IP Address
In 3:Getting Started , we described how to assign an IP address using
DeviceInstaller. This section covers other methods for assigning an IP address
over the network.
Note: You can also assign the IP address using a serial connection. (See Using
the Serial Port on page 4-2.)
DHCP
The unit ships with a default IP address of 0.0.0.0, which automatically enables
DHCP. If a DHCP server exists on the network, it will provide the unit with an IP
address, gateway address, and subnet mask when the unit boots up.
You can use the DeviceInstaller software to search the network for the IP
address your unit has been assigned by the DHCP server and add it to the
managed list.
Note: This DHCP address does not appear in the unit’s Setup Mode and
Web-Manager screens. You can, however, determine your unit’s DHCP-
assigned IP address in Monitor Mode. When you enter Monitor Mode
from the serial port with network connection enabled (see on page
7-1 )
and issue the NC (Network Communication) command, you will see the
unit’s IP configuration.
AutoIP
The unit ships with a default IP address of 0.0.0.0, which automatically enables
Auto IP within the unit. AutoIP is an alternative to DHCP that allows hosts to
automatically obtain an IP address in smaller networks that may not have a
DHCP server. A range of IP addresses (from 169.254.0.1 to 169.254.255.1) has
been explicitly reserved for AutoIP-enabled devices. The range of Auto IP
addresses is not to be used over the Internet.
If your unit cannot find a DHCP server, and you have not manually assigned an
IP address to it, the unit automatically selects an address from the AutoIP
reserved range. Then, your unit sends out a (ARP) request to other nodes on the
same network to see whether the selected address is being used.
If the selected address is not in use, then the unit uses it for local subnet
communication.
If another device is using the selected IP address, the unit selects another
address from the AutoIP range and reboots. After reboot, the unit sends out
another ARP request to see if the selected address is in use, and so on.
AutoIP is not intended to replace DHCP. The unit will continue to look for a
DHCP server on the network. If it finds a DHCP server, the unit will switch to the
DHCP server-provided address and reboot.
Note: If a DHCP server is found, but it denies the request for an IP
address, the unit does not attach to the network, but waits and retries.
AutoIP can be disabled by setting the unit’s IP address to 0.0.1.0. This setting
enables DHCP but disables AutoIP.
9-4 XPort™ User Guide