User manual

Addressing Schemes B-
5
Reserved Addresses
In most IP machines, setting all the bits in the host portion of an
IP address to 1 indicates a broadcast to all nodes on the
network. In the Class B network described above, an address of
128.5.255.255 is a network broadcast address meaning the
packet is destined for all nodes on the entire Class B network.
128.5.63.255 would be a broadcast address indicating that the
packet is destined for all nodes on subnet 63.
However, one rare version of TCP/IP instead considers an
address in which the host bits are all set to 0 a broadcast
address. On the NETServer, you configure for this difference as
part of basic setup. See the CLI Reference Guide.
On networks with a “high” broadcast address, setting all bits to
0 simply means “this host” or “this network” and is usually
used only when a node does not know its own network or node
address (and is probably requesting that information).
One other reserved address is 127.x.x.x. The contents of the last
three bytes are not important. This is a loopback address used
for troubleshooting. It allows you to verify that a device can
send something to itself. A packet with this address should
never actually leave the machine that originated it.