Configure TCP/IP - MCSA Windows Server 2012 R2: Installation and Configuration Study Guide - page 394

network and host addresses, the number of bits to mask is important. For example, in a
Class A network, 8 bits are masked, making the default subnet mask 255.0.0.0; in a Class C,
24 bits are masked, making the default subnet mask 255.255.255.0.
Some IP addresses are reserved for special purposes and shouldn't be assigned to nodes.
Table 8.3 describes some of the reserved IP addresses. See RFC 3330 for others.

Table 8.3 Special network addresses

Address Function

Entire IP address set to all 0s Depending on the mask, this network (that is, the network

or subnet of which you are currently a part) or this host on
this network.

A routing table entry of all 0s
with a mask of all 0s

Used as the default gateway entry. Any destination
address masked by all 0s produces a match for the all 0s
reference address. Because the mask has no 1s, this is the
least desirable entry, but it will be used when no other
match exists.

Network address 127 Reserved for loopback tests. Designates the local node,

and it allows that node to send a test packet to itself with-
out generating network traffic.

Node address of all 0s Used when referencing a network without referring to any

specific nodes on that network. Usually used in routing
tables.

Node address of all 1s Broadcast address for all nodes on the specified net-

work, also known as a directed broadcast . For example,
128.2.255.255 means all nodes on the Class B network
128.2. Routing this broadcast is configurable on certain
routers.

169.254.0.0 with a mask of
255.255.0.0

The “link-local” block used for autoconfiguration and
communication between devices on a single link. Commu-
nication cannot occur across routers. Microsoft uses this
block for Automatic Private IP Addressing (APIPA).

Entire IP address set to all 1s
(same as 255.255.255.255)
10.0.0.0/8
172.16.0.0 to 172.31.255.255

Broadcast to all nodes on the current network; sometimes
called a limited broadcast or an all-1s broadcast . This
broadcast is not routable.

192.168.0.0/16 The private-use blocks for Classes A, B, and C. As noted

in RFC 1918, the addresses in these blocks must never
be allowed into the Internet, making them acceptable for
simultaneous use behind NAT servers and non-Internet-
connected IP networks.