User`s guide

Introduction
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destination device. If the device is on the network, it will respond
with its hardware address.
Reverse Address Resolution Protocol (RARP)
If the ATX is not configured with an IP address, it uses reverse ARP
(RARP), to send out broadcasts of its physical hardware address to
find its IP address.
Proxy ARP
Proxy ARP provides a mechanism whereby the ATX can respond
to an ARP request on behalf of a device that is located on a
network behind it. This is particularly helpful if you are using IP
subnetting. The ATX could respond to a request on behalf of
devices that it knows about, in effect acting as a proxy agent for
that device.
BOOTP
The BOOTstrap Protocol (BOOTP) uses IP to deliver a packet
including an IP address, the address of a router and the server
address. Enabling the BOOTP relay option is useful in
environments where you have a diskless client and its server is on
a network on the other side of the ATX. When the client boots up, it
sends out a broadcast requesting the software it needs to
download. If bootp is not enabled, the ATX won’t forward the
broadcast to the network where the server is located. This may also
be used to relay DHCP frames.
IPM
Enable IP multicasting. IP multicasting is the transmission of IP
packets to a host group. A host group is a set of hosts identified by
a single IP address.