Classless Inter-Domain Routing
IP/CIDR
Mask
Hosts (*)
Class
0.0.0.0/0
a.0.0.0/1
a.0.0.0/2
a.0.0.0/3
.0.0.0/4
a.0.0.0/5
a.0.0.0/6
a.0.0.0/7
a.0.0.0/8
a.b.0.0/9
a.b.0.0/10
a.b.0.0/11
a.b.0.0/12
a.b.0.0/13
a.b.0.0/14
a.b.0.0/15
a.b.0.0/16
000.000.000.000
128.000.000.000
192.000.000.000
224.000.000.000
240.000.000.000
248.000.000.000
252.000.000.000
254.000.000.000
255.000.000.000
255.128.000.000
255.192.000.000
255.224.000.000
255.240.000.000
255.248.000.000
255.252.000.000
255.254.000.000
255.255.000.000
4,294,967,296
2,147,483,648
1,073,741,824
536,870,912
268,435,456
134,217,728
67,108,864
33,554,432
16,777,216
8,388,608
4,194,304
2,097,152
1,048,576
524,288
262,144
131,072
65,536
256 A
128 A
64 A
32 A
16 A
8A
4A
2A
256 B = 1 A
128 B
64 B
32 B
16 B
8B
4B
2B
256 C = 1 B
a.b.c.0/17
a.b.c.0/18
a.b.c.0/19
a.b.c.0/20
a.b.c.0/21
a.b.c.0/22
a.b.c.0/23
a.b.c.0/24
a.b.c.d/25
a.b.c.d/26
a.b.c.d/27
a.b.c.d/28
a.b.c.d/29
a.b.c.d/30
a.b.c.d/31
a.b.c.d/32
255.255.128.000
255.255.192.000
255.255.224.000
255.255.240.000
255.255.248.000
255.255.252.000
255.255.254.000
255.255.255.000
255.255.255.128
255.255.255.192
255.255.255.224
255.255.255.240
255.255.255.248
255.255.255.252
255.255.255.254
255.255.255.255
32,768
16,384
8,192
4,096
2,048
1,024
512
256
128
64
32
16
8
4
2
1
128 C
64 C
32 C
16 C
8C
4C
2C
1C
1/2 C
1/4 C
1/8 C
1/16 C
1/32 C
1/64 C
1/128 C
1/256 C
www.rickfreyconsulting.com
[email protected]
(903) 245-1557
Private IP Addresses
IP Address
Range
Number of
Addresses
Description
CIDR Notation
Subnet
Mask
10.0.0.0 10.255.255.255
16,777,216
Entire
Class A
10.0.0.0/8
255.0.0.0
172.16.0.0 172.31.255.255
1,048,576
16 Contiguous
Class Bs
172.16.0.0/12
255.240.0.0
192.168.0.0 192.168.255.255
65,536
256 Contiguous
Class Cs
192.168.0.0/16 255.255.0.0
16 bit Autonomous Numbers (ASNs)
Address
Range
Number of
Addresses
0 -65535
65536
1
1
0
23456
64512 - 65534
65535
1
Notes
16 Bit ASN Range
Reserved by IANA
Bridge Between 16 Bit & 32 Bit ASNs
Reserved for Private Use
Reserved by IANA
32 bit Autonomous Numbers (ASNs)
0.0 65535.65535
2.0 - 2.1023
3.0 - 3.1023
4.0 - 4.1023
5.0 - 5.1023
6.0 - 6.1023
4,294,967,295
32 Bit ASN Range
1024
1024
1024
1024
1024
APNIC
RIPR NCC
LACNIC
AfrNIC
ARIN
All other ASNs are Reserved
www.rickfreyconsulting.com
[email protected]
(903) 245-1557