IP Address Ranges
see tables below
Class As
Ever wonder who owns the class A IP networks? These are the blocks of
addresses with initial octet 1 through 128, and they are allocated
entirely to one organization (or used to be, anyway). For example,
IBM owns all the addresses from 9.0.0.0 to 9.255.255.255. This range
can hold approximately 16 million individual hosts (computers). Class
A networks are almost never given out anymore, since very few
organizations can actually use all those addresses.
Anyway, here's the list:
Number Organization
 
3 General Electric
4 BBN Planet
6 Army Information Systems Center
8 BBN (corporate)
9 IBM
11 DoD Intel Information Systems
12 AT&T
13 Xerox PARC
14 Public Data Network
15 HP
16 DEC
17 Apple
18 MIT
19 Ford
20 Computer Sciences Corporation
21 DDNRVN
22 Defense Information Systems Agency
25 Royal Signals and Radar Establishment
26 Defense Information Systems Agency
28 ARPA DSI JPO
29 Defense Information Systems Agency
30 Defense Information Systems Agency
32 Norsk Informasjonsteknologi
33 DLA Systems Automation Center
34 Halliburton Co.
35 Merit Network Inc.
36 Stanford
38 PSI
40 Eli Lilly and Co.
43 Japan Inet
44 Amateur Radio Digital Communications
45 Interop Show Network
47 BellNorthern Research
48 Prudential
49 Joint Tactical Command, Control and Communications Agency
51 Department of Social Security of UK
52 Du Pont
53 cap debis ccs
54 Merck
55 Army National Guard Bureau
56 U.S. Postal Service
57 Societe Internationale de Telecommunications Aeronautiques
61 Asia Pacific Network Information Center
62 European Regional Internet Registry/RIPE NCC
63 InterNIC
Most of these organizations were involved in the early development of
the Internet, so they got networks assigned before IANA (Internet
Assigned Numbers Authority) stopped giving out class As. Several are
assigned to military organizations, but I think it's a bit of a
stretch to claim "the only people with class A networks also have
nuclear weapons," as I saw someone assert somewhere (typical net.hyperbole)
Class Bs
Class B  Class B is used for mediumsized networks. A good example is
a large college campus. IP addresses with a first octet from 128 to 191 are part
of this class. Range 128.x.x.x to 191.x.x.x
Class Cs
To communicate on the Internet, you must use addresses that have been allocated by the Internet Network Information Center (InterNIC). Addresses allocated by InterNIC can receive traffic from Internet locations and are known as public addresses. A typical small business or home office is allocated a public address (or addresses) from its Internet service provider (ISP), who has received a range of public addresses.
To allow multiple computers in the small office or home office to communicate on the Internet, each computer must have its own public address. This requirement places great stress on the available pool of public addresses.
To relieve this stress, the InterNIC has provided for an address reuse scheme by reserving network IDs for private internetworks. The private network IDs include:

10.0.0.0 with the subnet mask 255.0.0.0

172.16.0.0 with the subnet mask 255.240.0.0

192.168.0.0 with the subnet mask 255.255.0.0
For more information about portions of the IP address space that is reserved for private intranets, see RFC 1597, "Address Allocation for Private Internets." All addresses in these ranges are known as private addresses.
Private addresses cannot receive traffic from Internet locations. Therefore,
if an intranet is using private addresses and communicating with Internet locations,
the private address must be translated to a public address. A network address
translator (NAT) is placed between an intranet that uses private addresses and
the Internet, which uses public addresses. Outgoing packets from the intranet
have their private addresses translated by the NAT into public addresses. Incoming
packets from the Internet have their public addresses translated by the NAT
into private addresses. This is what simple home routers use.
Loopback  The IP address
127.0.0.0 is used as the loopback address. This means that it is used
by the host computer to send a message back to itself. It is commonly used for
troubleshooting and network testing.
Class D  Used for multicasts, Class D is slightly different
from the first three classes. 224. 24.53.107
Class E  Class E is used for experimental purposes
only. Like Class D, it is different from the first three classes. Net Host or
Node 232. 24.53.107
Broadcast  Messages that are intended for all computers
on a network are sent as broadcasts. These messages always use the IP address
255.255.255.255.
Listed below are the IP address tables for Class A, Class
B and Class C. Each table presents:

The Maximum number of Subnets for a given mask 

The Maximum number of hosts for a given mask 

The first and second subnet information,as follows:

The Subnet number which is used for routing (this is the number displayed in routing
tables) 

The valid IP address ranges for the subnets 

The IP subnet broadcast address 


Please note, the information on the first and last subnets has not been displayed as
some hosts are unable to use these subnets, see RFC 1519 or 1812 for more information 

No
liability is taken for the correctness of the information
supplied on this page or any other page. 

No:
of Subnet bits 
Subnet
Mask 
Subnet Mask
in Hex 
No:
Subnets 
No:
Hosts 
Max
No: of Hosts (Nets * Hosts) 
1st Subnet Addr. Used for Routing 
1st Subnet Addr Range 
1st Subnet B'cast 
2nd Subnet Addr. Used for Routing 
2nd Subnet Addr Range 
2nd Subnet B'cast 
2 
255.192.0.0 
FF.C0.0.0 
2 
4194302 
8388604 
X.64.0.0 
X.64.0.1 to
X.127.255.254 
X.127.255.255 
X.128.0.0 
X.128.0.1 to
X.191.255.254 
X.191.255.255 
3 
255.224.0.0 
FF.E0.0.0 
6 
2097150 
12582900 
X.32.0.0 
X.32.0.1 to
X.63.255.254 
X.63.255.255 
X.64.0.0

X.64.0.1 to
X.95.0.254 
X.95.255.255

4 
255.240.0.0 
FF.F0.0.0 
14 
1048574 
14680036 
X.16.0.0 
X.16.0.1 to X.31.255.254 
X.31.255.255

X.32.0.0

X.32.0.1 to
X.47.255.254 
X.47.255.255 
5 
255.248.0.0 
FF.F8.0.0 
30 
524286 
15728580 
X.8.0.0 
X.8.0.1 to
X.15.255.254 
X.15.255.255 
X.16.0.0 
X.16.0.1 to
X.23.255.254 
X.23.255.255 
6 
255.252.0.0 
FF.FC.0.0 
62 
262142 
16252804 
X.4.0.0 
X.4.0.1 to
X.7.255.254 
X.7.255.255 
X.8.0.0 
X.8.0.1 to
X.11.255.254 
X.11.255.255 
7 
255.254.0.0 
FF.FE.0.0 
126 
131070 
16514820 
X.2.0.0 
X.2.0.1 to
X.3.255.254 
X.3.255.255 
X.4.0.0 
X.4.0.1 to
X.5.255.254 
X.5.255.255 
8 
255.255.0.0 
FF.FF.0.0 
254 
65534 
16645636 
X.1.0.0 
X.1.0.1 to
X.1.255.254 
X.1.255.255 
X.2.0.0 
X.2.0.1 to
X.2.255.254 
X.2.255.255

9 
255.255.128.0 
FF.FF.80.0 
510 
32766 
16710660 
X.0.128.0 
X.0.128.1 to
X.0.255.254 
X.0.255.255

X.1.0.0 
X.1.0.1 to
X.1.127.254 
X.1.127.255

10 
255.255.192.0 
FF.FF.C0.0 
1022 
16382 
16742404 
X.0.64.0 
X.0.64.1 to
X.0.127.254 
X.0.127.255

X.0.128.0

X.0.128.1 to
X.0.191.254 
X.0.191.255

11 
255.255.224.0 
FF.FF.E0.0 
2046 
8190 
16756740 
X.0.32.0 
X.0.32.1 to X.0.63.254 
X.0.63.255

X.0.64.0

X.0.64.1 to
X.0.95.254 
X.0.95.255

12 
255.255.240.0 
FF.FF.F0.0 
4094 
4094 
16760836 
X.0.16.0

X.0.16.1 to
X.0.31.254 
X.0.31.255

X.0.32.0

X.0.32.1 to
X.0.47.254 
X.0.47.255

13 
255.255.248.0 
FF.FF.F8.0 
8190 
2046 
16756740 
X.0.8.0 
X.0.8.1 to
X.0.15.254 
X.0.15.255

X.0.16.0

X.0.16.1 to
X.0.23.254 
X.0.23.255

14 
255.255.252.0 
FF.FF.FC.0 
16382 
1022 
16742404 
X.0.4.0 
X.0.4.1 to
X.0.7.254 
X.0.7.255

X.0.8.0 
X.0.8.1 to
X.0.11.254 
X.0.11.255

15 
255.255.254.0 
FF.FF.FE.0 
32766 
510 
16710660 
X.0.2.0 
X.0.2.1 to
X.0.3.254 
X.0.3.255 
X.0.4.0 
X.0.4.1 to
X.0.5.254 
X.0.5.255 
16 
255.255.255.0 
FF.FF.FF.0 
65534 
254 
16645636 
X.0.1.0 
X.0.1.1 to
X.0.1.254 
X.0.1.255

X.0.2.0 
X.0.2.1 to
X.0.2.254 
X.0.2.255

17 
255.255.255.128 
FF.FF.FF.80 
131070 
126 
16514820 
X.0.0.128 
X.0.0.129 to
X.0.0.254 
X.0.0.255

X.0.1.0 
X.0.1.1 to
X.0.1.126 
X.0.1.127 
18 
255.255.255.192 
FF.FF.FF.C0 
262142 
62 
16252804 
X.0.0.64

X.0.0.65 to
X.0.0.126 
X.0.0.127 
X.0.0.128

X.0.0.129 to
X.0.0.190 
X.0.0.191

19 
255.255.255.224 
FF.FF.FF.E0 
524286 
30 
15728580 
X.0.0.32 
X.0.0.33 to
X.0.0.62 
X.0.0.63 
X.0.0.64

X.0.0.65 to
X.0.0.94 
X.0.0.95

20 
255.255.255.240 
FF.FF.FF.F0 
1048574 
14 
14680036 
X.0.0.16 
X.0.0.17 to
X.0.0.30 
X.0.0.31

X.0.0.32

X.0.0.33 to
X.0.0.46 
X.0.0.47

21 
255.255.255.248 
FF.FF.FF.F8 
2097150 
6 
12582900 
X.0.0.8 
X.0.0.9 to
X.0.0.14 
X.0.0.15

X.0.0.16

X.0.0.17 to
X.0.0.22 
X.0.0.23

22 
255.255.255.252 
FF.FF.FF.FC 
4194302 
2 
8388604 
X.0.0.4 
X.0.0.5
to X.0.0.6 
X.0.0.7 
X.0.0.8 
X.0.0.9 to
X.0.0.10 
X.0.0.11

tNo: of Subnet bitss 
Subnet
Mask 
Subnet Mask
in Hex 
No:
Subnets 
No:
Hosts 
Max
No: of Hosts (Nets * Hosts) 
1st Subnet Addr. Used for Routing 
1st Subnet Addr Range 
1st Subnet B'cast 
2nd Subnet Addr. Used for Routing 
2nd Subnet Addr Range 
2nd Subnet B'cast 
2 
255.255.192.0 
FF.FF.C0.0 
2 
16382 
32764 
X.Y.64.0 
X.Y.64.1 to X.Y.127.254 
X.Y.127.255 
X.Y.128.0 
X.Y.128.1 to X.Y.191.254 
X.Y.191.255 
3 
255.255.224.0 
FF.FF.E0.0 
6 
8190 
49140 
X.Y.32.0 
X.Y.32.1 to X.Y.63.254 
X.Y.63.255 
X.Y.64.0 
X.Y.64.1 to X.Y.95.254 
X.Y.95.255 
4 
255.255.240.0 
FF.FF.F0.0 
14 
4094 
57316 
X.Y.16.0 
X.Y.16.1 to X.Y.31.254 
X.Y.31.255 
X.Y.32.0 
X.Y.32.1 to X.Y.47.254 
X.Y.47.255 
5 
255.255.248.0 
FF.FF.F8.0 
30 
2046 
61380 
X.Y.8.0 
X.Y.8.1 to X.Y.15.254 
X.Y.15.255 
X.Y.16.0 
X.Y.16.1 to X.Y.23.254 
X.Y.23.255 
6 
255.255.252.0 
FF.FF.FC.0 
62 
1022 
63364 
X.Y.4.0 
X.Y.4.1 to X.Y.7.254 
X.Y.7.255 
X.Y.8.0 
X.Y.8.1 to X.Y.11.254 
X.Y.11.255 
7 
255.255.254.0 
FF.FF.FE.0 
126 
510 
64260 
X.Y.2.0 
X.Y.2.1 to X.Y.3.254 
X.Y.3.255 
X.Y.4.0 
X.Y.4.1 to X.Y.5.254 
X.Y.5.255 
8 
255.255.255.0 
FF.FF.FF.0 
254 
254 
64516 
X.Y.1.0 
X.Y.1.1 to X.Y.254 
X.Y.1.255 
X.Y.2.0 
X.Y.2.1 to X.Y.2.254 
X.Y.2.255 
9 
255.255.255.128 
FF.FF.FF.80 
510 
126 
64260 
X.Y.0.128 
X.Y.0.129 to X.Y.0.254 
X.Y.0.255 
X.Y.1.0 
X.Y.1.1 to X.Y.1.126 
X.Y.1.127 
10 
255.255.255.192 
FF.FF.FF.C0 
1022 
62 
63364 
X.Y.0.64 
X.Y.0.65 to X.Y.0.126 
X.Y.0.127 
X.Y.0.128 
X.Y.0.129 to X.Y.0.190 
X.Y.0.191 
11 
255.255.255.224 
FF.FF.FF.E0 
2046 
30 
61380 
X.Y.0.32 
X.Y.0.33 to X.Y.0.62 
X.Y.0.63 
X.Y.0.64 
X.Y.0.65 to X.Y.0.94 
X.Y.0.95 
12 
255.255.255.240 
FF.FF.FF.F0 
4094 
14 
57316 
X.Y.0.16 
X.Y.0.17 to X.Y.0.30 
X.Y.0.31 
X.Y.0.32 
X.Y.0.33 to X.Y.0.46 
X.Y.0.47 
13 
255.255.255.248 
FF.FF.FF.F8 
8190 
6 
49140 
X.Y.0.8 
X.Y.0.9 to X.Y.0.14 
X.Y.0.15 
X.Y.0.16 
X.Y.0.17 to X.Y.0.22 
X.Y.0.23 
14 
255.255.255.252 
FF.FF.FF.FC 
16382 
2 
32764 
X.Y.0.4 
X.Y.0.5 to X.Y.0.6 
X.Y.0.7 
X.Y.0.8 
X.Y.0.9 to X.Y.0.10 
X.Y.0.11 
No:
of Subnet bits 
Subnet
Mask 
Subnet Mask in
Hex 
No:
Subnets 
No:
Hosts 
Max
No: of Hosts (Nets * Hosts) 
1st Subnet Addr. Used for Routing 
1st Subnet Addr Range 
1st Subnet B'cast 
2nd Subnet Addr. Used for Routing 
2nd Subnet Addr Range 
2nd Subnet B'cast 
2 
255.255.255.192 
FF.FF.FF.C0 
2 
62 
124 
X.Y.Z.64 
X.Y.Z.65 to X.Y.Z.126 
X.Y.Z.127 
X.Y.Z.128 
X.Y.Z.129 to X.Y.Z.190 
X.Y.Z.191 
3 
255.255.255.224 
FF.FF.FF.E0 
6 
30 
180 
X.Y.Z.32 
X.Y.Z.33 to X.Y.Z.62 
X.Y.Z.63 
X.Y.Z.64 
X.Y.Z.65 to X.Y.Z.94 
X.Y.Z.95 
4 
255.255.255.240 
FF.FF.FF.F0 
14 
14 
196 
X.Y.Z.16 
X.Y.Z.17 to X.Y.Z.30 
X.Y.Z.31 
X.Y.Z.32 
X.Y.Z.33 to X.Y.Z.46 
X.Y.Z.47 
5 
255.255.255.248 
FF.FF.FF.F8 
30 
6 
180 
X.Y.Z.8 
X.Y.Z.9 to X.Y.Z.14 
X.Y.Z.15 
X.Y.Z.16 
X.Y.Z.17 to X.Y.Z.22 
X.Y.Z.23 
6 
255.255.255.252 
FF.FF.FF.FC 
62 
2 
124 
X.Y.Z.4 
X.Y.Z.5 to X.Y.Z.6 
X.Y.Z.7 
X.Y.Z.8 
X.Y.Z.9 to X.Y.Z.10 
X.Y.Z.11 
