1.3 IPv4 Subnetting - Paiet/Tech-Journal-for-Everything GitHub Wiki
1.3 IPv4 Subnetting
Class A - 255.0.0.0 - 1 - 126
Class B - 255.255.0.0 - 128 - 191
Class C - 255.255.255.0 - 192 - 223
Host A: 192.168.0.222
Host B: 192.168.1.57
Host C: 192.168.0.33
Host D: 192.168.1.100
Mask: 255.255.255.0
NetworkID.HostID
209.251.159.133
209.151.159.77
255.255.255.0
CIDR - Classless Inter-Domain Routing
72.10.35.44
255.0.0.0 - 11111111.00000000.00000000.00000000
255.255.0.0 - 11111111.11111111.00000000.00000000
255.255.255.0 - 11111111.11111111.11111111.00000000
255.255.x.0 11111111.11111111.11110000.00000000
11111111 - 255
11111110 - 254
11111100 - 252
11111000 - 248
11110000 - 240
11100000 - 224
11000000 - 192
10000000 - 128
00000000 - 0
10000000.00000000.00000000.00000000 - 128.0.0.0
11000000.00000000.00000000.00000000 - 192.0.0.0
11100000.00000000.00000000.00000000 - 224.0.0.0
11110000.00000000.00000000.00000000 - 240.0.0.0
11111000.00000000.00000000.00000000 - 248.0.0.0
11111100.00000000.00000000.00000000 - 252.0.0.0
11111110.00000000.00000000.00000000 - 254.0.0.0
11111111.00000000.00000000.00000000 - 255.0.0.0 - Class A
11111111.10000000.00000000.00000000 - 255.128.0.0
11111111.11000000.00000000.00000000 - 255.192.0.0
11111111.11100000.00000000.00000000 - 255.224.0.0
11111111.11110000.00000000.00000000 - 255.240.0.0
11111111.11111000.00000000.00000000 - 255.248.0.0
11111111.11111100.00000000.00000000 - 255.252.0.0
11111111.11111110.00000000.00000000 - 255.254.0.0
11111111.11111111.00000000.00000000 - 255.255.0.0 - Class B
11111111.11111111.10000000.00000000 - 255.255.128.0
11111111.11111111.11000000.00000000 - 255.255.192.0
11111111.11111111.11100000.00000000 - 255.255.224.0
11111111.11111111.11110000.00000000 - 255.255.240.0
11111111.11111111.11111000.00000000 - 255.255.248.0
11111111.11111111.11111100.00000000 - 255.255.252.0
11111111.11111111.11111110.00000000 - 255.255.254.0
11111111.11111111.11111111.00000000 - 255.255.255.0 - Class C
11111111.11111111.11111111.10000000 - 255.255.255.128
11111111.11111111.11111111.11000000 - 255.255.255.192
11111111.11111111.11111111.11100000 - 255.255.255.224
11111111.11111111.11111111.11110000 - 255.255.255.240
11111111.11111111.11111111.11111000 - 255.255.255.248
11111111.11111111.11111111.11111100 - 255.255.255.252
11111111.11111111.11111111.11111110 - 255.255.255.254
128 - 1 128+64+32+16 = 128+64=192+32=224+16=240
64 - 1 8+4+2+1 = 12+2=14+1=15 255-15=240
32 - 1
16 - 1
8 - 0
4 - 0
2 - 0
1 - 0
VLSM - Variable Length Subnet Mask
Subnetting
Subnetting - Dividing a network up to make multiple smaller networks
Supernetting - Combining networks to make a single larger network
192.168.0.55
192.186.0.47
255.255.255.0
Converting all octets:
|
192.168.53.111 - 11000000.10101000.0011|0101.01111000
192.168.47.8 - 11000000.10101000.0010|1111.00001000
255.255.240.0 - 11111111.11111111.1111|0000.00000000
|
Converting the "Action Octet"
|
192.168.111.240 111 - 0|0110101
192.168.200.11 200 - 1|1001000
255.255.128.0 128 - 1|0000000
|
Converting as few bits as possible:
|
192.168.217.44 217 - 11|
192.168.63.9 63 - 00|
255.255.192.0 192 - 11|000000
|
128 - 0 168 - 128 = 40 - 32 = 8 - 8 = 0
64 - 1
32 - 1
16 - 1
8 - 1
4 - 0
2 - 0
1 - 0
Subnet Shorthand Notation
255.255.255.0 - 11111111.11111111.11111111.00000000
/24
192.168.0.100/24
/0 - All Networks
/8 - Class A - 255.0.0.0
/16 - Class B - 255.255.0.0
/24 - Class C - 255.255.255.0
/32 - A single machine
Class A - 10.0.0.0/8
Class B - 172.16.0.0/16
Class C - 192.168.0.0/24
192.168.53.111
192.168.47.8
255.255.255.0
192.168.53.111
192.168.47.8
255.255.0.0
|
192.168.53.111 - 11000000.10101000.0011|0101.01111000
192.168.47.8 - 11000000.10101000.0010|1111.00001000
255.255.240.0 - 11111111.11111111.1111|0000.00000000
|
Network Contains Three Types of IPs:
* Subnet Reference - Very first IP. Identifies the subnet
* Host IP - Everything between the subnet IP and the broadcast IP
* Broadcast - Very last IP. Used to communicate with all hosts
Class A (/8)
10.0.0.0/8
255.0.0.0
IP Range
Subnet: 10.0.0.0
First Usable: 10.0.0.1
Last Usable: 10.255.255.254
Broadcast: 10.255.255.255
Class B (/16)
172.16.0.0/16
255.255.0.0
IP Range
Subnet: 172.16.0.0
First Usable: 172.16.0.1
Last Usable: 172.16.255.254
Broadcast: 172.16.255.255
Class C (/24)
192.168.0.0/24
255.255.255.0
IP Range
Subnet: 192.168.0.0
First Usable: 192.168.0.1
Last Usable: 192.168.0.254
Broadcast: 192.168.0.255
Class ? (/?)
192.168.47.8
255.255.240.0
|
192.168.47.8: 11000000.10101000.00101111|.00001000 192.168.47.8
Subnet: 11000000.10101000.00101111|.00000000 192.168.47.0
First Usable: 11000000.10101000.00101111|.00000001 192.168.47.1
Last Usable: 11000000.10101000.00101111|.11111110 192.168.47.254
Broadcast: 11000000.10101000.00101111|.11111111 192.168.47.255
255.255.255.0: 11111111.11111111.11111111|.00000000 255.255.255.0
|
|
192.168.47.8: 11000000.10101000.0010|1111.00001000 192.168.47.8
Subnet: 11000000.10101000.0010|0000.00000000 192.168.32.0
First Usable: 11000000.10101000.0010|0000.00000001 192.168.32.1
Last Usable: 11000000.10101000.0010|1111.11111110 192.168.47.254
Broadcast: 11000000.10101000.0010|1111.11111111 192.168.47.255
255.255.240.0: 11111111.11111111.1111|0000.00000000 255.255.240.0
|
128 - 0
64 - 1 32 + 8 + 4 + 2 + 1 = 47
32 - 1 80 - 64 = 16 - 16 = 0
16 - 1 80 = 01010000
8 - 1 64 + 32 + 16 + 8 + 4 + 2 + 1 = 127
4 - 1
2 - 1
1 - 1
80 Computers
80 = 1010000 = 80
?? = 0000000 = 0
?? = 1111111 = 127
192.168.47.0/24
|
192.168.47.0: 11000000.10101000.00101111|.00000000 192.168.47.0
Subnet: 11000000.10101000.00101111|.00000000 192.168.47.0
First Usable: 11000000.10101000.00101111|.00000001 192.168.47.1
Last Usable: 11000000.10101000.00101111|.11111110 192.168.47.254
Broadcast: 11000000.10101000.00101111|.11111111 192.168.47.255
255.255.255.0: 11111111.11111111.11111111|.00000000 255.255.255.0
|
Divide 192.168.47.0/24 in half
Create 192.168.47.0/25
192.168.47.0/25
|
192.168.47.0: 11000000.10101000.00101111.0|0000000 192.168.47.0
Subnet: 11000000.10101000.00101111.0|0000000 192.168.47.0
First Usable: 11000000.10101000.00101111.0|0000001 192.168.47.1
Last Usable: 11000000.10101000.00101111.0|1111110 192.168.47.126
Broadcast: 11000000.10101000.00101111.0|1111111 192.168.47.127
255.255.255.?: 11111111.11111111.11111111.1|0000000 255.255.255.128
|
|
192.168.47.?: 11000000.10101000.00101111.1|0000000 192.168.47.128
Subnet: 11000000.10101000.00101111.1|0000000 192.168.47.128
First Usable: 11000000.10101000.00101111.1|0000001 192.168.47.129
Last Usable: 11000000.10101000.00101111.1|1111110 192.168.47.254
Broadcast: 11000000.10101000.00101111.1|1111111 192.168.47.255
255.255.255.?: 11111111.11111111.11111111.1|0000000 255.255.255.128
|
Binary Bits
B
0
1
BB
00
01
10
11
BBB
000
001
010
011
100
101
110
111
Double the size of 192.168.47.0/24
Create 192.168.47.0/23
192.168.47.0/24
|
192.168.47.0: 11000000.10101000.0010111|1.00000000 192.168.47.0
Subnet: 11000000.10101000.0010111|0.00000000 192.168.46.0
First Usable: 11000000.10101000.0010111|0.00000001 192.168.46.1
Weird IP #1: 11000000.10101000.0010111|0.11111111 192.168.46.255
Weird IP #2: 11000000.10101000.0010111|1.00000000 192.168.47.0
Last Usable: 11000000.10101000.0010111|1.11111110 192.168.47.254
Broadcast: 11000000.10101000.0010111|1.11111111 192.168.47.255
255.255.255.0: 11111111.11111111.1111111|0.00000000 255.255.254.0
|
192.168.46.255
192.168.47.0
Which of the following are not valid IPs for use on a host:
192.168.0.0/24
192.168.0.53/24
192.168.0.272/24
192.168.1.0/23