User manual

Electro Industries/GaugeTech

Doc #: E113-7-07 V1.04 2-2

AutoIP assigns a random valid address to the Ethernet Interface in the range of 169.254.x.1 to

169.254.x.1 where x can be between 0 and 255. This range of IP addresses is not to be used over the

Internet. If the Ethernet Interface has not been configured manually and cannot find a DHCP server,

it automatically chooses an address from the reserved range. The Ethernet Interface then uses the

Address Resolution Protocol (ARP) to send out a request asking if any node is using that address.

If another node is using the same address, the Ethernet Interface assigns another IP address, reboots

and repeats the sequence.

NOTE: AutoIP-enabled Ethernet Interfaces are constantly looking for DHCP servers. If a DHCP

server becomes available on the network, the AutoIP-enabled Ethernet Interface switches to the

DHCP server-provided address and the unit reboots. If the DHCP server exists but denies the

Ethernet Interface an IP address, the Ethernet Interface does not attach to the network, but waits and

retries.

• AutoIP allows a small network of AutoIP-enabled devices to be set up without any need for a

DHCP server or static IP addresses.

• AutoIP can be disabled by setting the IP address to 0.0.1.0. The 1 in the third octet is the

disabling factor.

2.6:

Setting

the

IP Address

The Ethernet Interface's IP address must be configured before a network connection is available. If

the IP address was not set automatically via DHCP, set it now using a network and the setup

(configuration) menu.

NETWORK PORT LOGIN

The ARP method is available under UNIX and Windows-based systems. The Ethernet Interface will

set its address from the first directed TCP/IP packet it receives.

CLEARING THE ARP TABLE

Clearing an entry in the ARP table should be performed before and after setting the IP Address that

you will be using. In command prompt, type the following (insert your IP Address). Then press the

Enter key.

ARP ON UNIX

On a Unix host, create an entry in the host's ARP table using the intended IP address and the

hardware address (or MAC Address) of the Ethernet Interface, which is found on the product label.

The label showing the MAC Address is found on the back panel (see section 1.2).

ARP ON WINDOWS

In order for the ARP command to work on Windows, the RP table on the PC must have at least one

arp -d 191.12.3.77

arp -s 191.12.3.77 00:20:4a:xx:xx:xx