IPv6

I. Format

IPv6 is an identifier with a fixed length of 128-bit1 (2128), which can represent more than 340 short-scale undecillion2 different values. This is a decimal number with 39 digits:

340 282 366 920 938 463 463 374 607 431 768 211 456

In contrast to the dot-decimal notation used in IPv4, which has four decimal 8-bit groups, IPv6 uses a colon-hexadecimal notation which has eight hexadecimal groups where each has 16 bit:

2001:0DB8:7654:0010:FEDC:0000:0000:3210

A hexadecimal number can reflect 16 (24) different values (0-9, A-F) which corresponds to exactly 4 bit. Since every group consists of four hexadecimal numbers, each group has 16 bit (216):

  •  16
  •  32
  •  48
  •  64
2001:0DB8:7654:0010:
  •  80
  •  96
  • 112
  • 128
FEDC:0000:0000:3210

IPv6 addresses are separated into two 64-bit parts, where the first on the left is the subnet prefix and the second on the right is the interface identifier (IID), which is a modified 64-Bit Extended Unique Identifier (EUI-64):

2001:0DB8:7654:0010:FEDC:0000:0000:3210

Example for often used ranges:

  • /16
  • /32
  • /56
  • /48
  • /64
2001:0DB8:7654:0010:
  • Interface Identifier
FEDC:0000:0000:3210

II. Compressed Format

Leading zeros in a group can be omitted as long the group would not end up empty:

2001:0DB8:0000:0010:FEDC:0000:0000:3210

► Result:

2001:DB8:0:10:FEDC:0:0:3210

Additionally, one or more groups only containing zeros (0 or 0000) can be replaced with a double colon (::). How­ever, this can be done only once per address, so one would usually choose the series with the most subsequent zero groups. In our example, that will be the red series:

2001:DB8:0:10:FEDC:0:0:3210

► Result:

2001:DB8:0:10:FEDC::3210

III. CIDR Tables

1. /128 to /64

(In 4-bit steps)

    • Prefix
    • IP Addresses
    • Prefix Address
    • /1283
    • 1
    • 0
    • ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff
    • /124
    • 16
    • 0
    • ffff:ffff:ffff:ffff:ffff:ffff:ffff:fff0
    • /120
    • 256
    • 0
    • ffff:ffff:ffff:ffff:ffff:ffff:ffff:ff00
    • /116
    • 4 096
    • 0
    • ffff:ffff:ffff:ffff:ffff:ffff:ffff:f000
    • /112
    • 65 536
    • 0
    • ffff:ffff:ffff:ffff:ffff:ffff:ffff:0
    • /108
    • 1 048 576
    • 0
    • ffff:ffff:ffff:ffff:ffff:ffff:fff0:0
    • /104
    • 16 777 216
    • 0
    • ffff:ffff:ffff:ffff:ffff:ffff:ff00:0
    • /100
    • 268 435 456
    • 0
    • ffff:ffff:ffff:ffff:ffff:ffff:f000:0
    • /96
    • 4 294 967 296
    • 1
    • ffff:ffff:ffff:ffff:ffff:ffff:0:0
    • /92
    • 68 719 476 736
    • 16
    • ffff:ffff:ffff:ffff:ffff:fff0:0:0
    • /88
    • 1 099 511 627 776
    • 256
    • ffff:ffff:ffff:ffff:ffff:ff00:0:0
    • /84
    • 17 592 186 044 416
    • 4 096
    • ffff:ffff:ffff:ffff:ffff:f000:0:0
    • /80
    • 281 474 976 710 656
    • 65 536
    • ffff:ffff:ffff:ffff:ffff:0:0:0
    • /76
    • 4 503 599 627 370 496
    • 1 048 576
    • ffff:ffff:ffff:ffff:fff0:0:0:0
    • /72
    • 72 057 594 037 927 936
    • 16 777 216
    • ffff:ffff:ffff:ffff:ff00:0:0:0
    • /68
    • 1 152 921 504 606 846 976
    • 268 435 456
    • ffff:ffff:ffff:ffff:f000:0:0:0
    • /644
    • 18 446 744 073 709 551 616
    • 4 294 967 296
    • ffff:ffff:ffff:ffff:0:0:0:0

2. /63 to /32

    • Prefix
    • /56s
    • /48s
    • /36s
    • Prefix Address
    • /63
    • 2
    • 0
    • 0
    • 0
    • ffff:ffff:ffff:fffe:0:0:0:0
    • /62
    • 4
    • 0
    • 0
    • 0
    • ffff:ffff:ffff:fffc:0:0:0:0
    • /61
    • 8
    • 0
    • 0
    • 0
    • ffff:ffff:ffff:fff8:0:0:0:0
    • /60
    • 16
    • 0
    • 0
    • 0
    • ffff:ffff:ffff:fff0:0:0:0:0
    • /59
    • 32
    • 0
    • 0
    • 0
    • ffff:ffff:ffff:ffe0:0:0:0:0
    • /58
    • 64
    • 0
    • 0
    • 0
    • ffff:ffff:ffff:ffc0:0:0:0:0
    • /57
    • 128
    • 0
    • 0
    • 0
    • ffff:ffff:ffff:ff80:0:0:0:0
    • /565
    • 256
    • 1
    • 0
    • 0
    • ffff:ffff:ffff:ff00:0:0:0:0
    • /55
    • 512
    • 2
    • 0
    • 0
    • ffff:ffff:ffff:fe00:0:0:0:0
    • /54
    • 1 024
    • 4
    • 0
    • 0
    • ffff:ffff:ffff:fc00:0:0:0:0
    • /53
    • 2 048
    • 8
    • 0
    • 0
    • ffff:ffff:ffff:f800:0:0:0:0
    • /52
    • 4 096
    • 16
    • 0
    • 0
    • ffff:ffff:ffff:f000:0:0:0:0
    • /51
    • 8 192
    • 32
    • 0
    • 0
    • ffff:ffff:ffff:e000:0:0:0:0
    • /50
    • 16 384
    • 64
    • 0
    • 0
    • ffff:ffff:ffff:c000:0:0:0:0
    • /49
    • 32 768
    • 128
    • 0
    • 0
    • ffff:ffff:ffff:8000:0:0:0:0
    • /486
    • 65 536
    • 256
    • 1
    • 0
    • ffff:ffff:ffff:0:0:0:0:0
    • /47
    • 131 072
    • 512
    • 2
    • 0
    • ffff:ffff:fffe:0:0:0:0:0
    • /46
    • 262 144
    • 1 024
    • 4
    • 0
    • ffff:ffff:fffc:0:0:0:0:0
    • /45
    • 524 288
    • 2 048
    • 8
    • 0
    • ffff:ffff:fff8:0:0:0:0:0
    • /44
    • 1 048 576
    • 4 096
    • 16
    • 0
    • ffff:ffff:fff0:0:0:0:0:0
    • /43
    • 2 097 152
    • 8 192
    • 32
    • 0
    • ffff:ffff:ffe0:0:0:0:0:0
    • /42
    • 4 194 304
    • 16 384
    • 64
    • 0
    • ffff:ffff:ffc0:0:0:0:0:0
    • /41
    • 8 388 608
    • 32 768
    • 128
    • 0
    • ffff:ffff:ff80:0:0:0:0:0
    • /40
    • 16 777 216
    • 65 536
    • 256
    • 0
    • ffff:ffff:ff00:0:0:0:0:0
    • /39
    • 33 554 432
    • 131 072
    • 512
    • 0
    • ffff:ffff:fe00:0:0:0:0:0
    • /38
    • 67 108 864
    • 262 144
    • 1 024
    • 0
    • ffff:ffff:fc00:0:0:0:0:0
    • /37
    • 134 217 728
    • 524 288
    • 2 048
    • 0
    • ffff:ffff:f800:0:0:0:0:0
    • /36
    • 268 435 456
    • 1 048 576
    • 4 096
    • 1
    • ffff:ffff:f000:0:0:0:0:0
    • /35
    • 536 870 912
    • 2 097 152
    • 8 192
    • 2
    • ffff:ffff:e000:0:0:0:0:0
    • /34
    • 1 073 741 824
    • 4 194 304
    • 16 384
    • 4
    • ffff:ffff:c000:0:0:0:0:0
    • /33
    • 2 147 483 648
    • 8 388 608
    • 32 768
    • 8
    • ffff:ffff:8000:0:0:0:0:0
    • /327
    • 4 294 967 296
    • 16 777 216
    • 65 536
    • 16
    • ffff:ffff:0:0:0:0:0:0

3. /31 to /0

    • Prefix
    • /23s
    • /16s
    • /12s
    • Prefix Address
    • /31
    • 2
    • 0
    • 0
    • 0
    • ffff:fffe:0:0:0:0:0:0
    • /30
    • 4
    • 0
    • 0
    • 0
    • ffff:fffc:0:0:0:0:0:0
    • /298
    • 8
    • 0
    • 0
    • 0
    • ffff:fff8:0:0:0:0:0:0
    • /28
    • 16
    • 0
    • 0
    • 0
    • ffff:fff0:0:0:0:0:0:0
    • /27
    • 32
    • 0
    • 0
    • 0
    • ffff:ffe0:0:0:0:0:0:0
    • /26
    • 64
    • 0
    • 0
    • 0
    • ffff:ffc0:0:0:0:0:0:0
    • /25
    • 128
    • 0
    • 0
    • 0
    • ffff:ff80:0:0:0:0:0:0
    • /24
    • 256
    • 0
    • 0
    • 0
    • ffff:ff00:0:0:0:0:0:0
    • /239
    • 512
    • 1
    • 0
    • 0
    • ffff:fe00:0:0:0:0:0:0
    • /22
    • 1 024
    • 2
    • 0
    • 0
    • ffff:fc00:0:0:0:0:0:0
    • /21
    • 2 048
    • 4
    • 0
    • 0
    • ffff:f800:0:0:0:0:0:0
    • /20
    • 4 096
    • 8
    • 0
    • 0
    • ffff:f000:0:0:0:0:0:0
    • /19
    • 8 192
    • 16
    • 0
    • 0
    • ffff:e000:0:0:0:0:0:0
    • /18
    • 16 384
    • 32
    • 0
    • 0
    • ffff:c000:0:0:0:0:0:0
    • /17
    • 32 768
    • 64
    • 0
    • 0
    • ffff:8000:0:0:0:0:0:0
    • /16
    • 65 536
    • 128
    • 1
    • 0
    • ffff:0:0:0:0:0:0:0
    • /15
    • 131 072
    • 256
    • 2
    • 0
    • fffe:0:0:0:0:0:0:0
    • /14
    • 262 144
    • 512
    • 4
    • 0
    • fffc:0:0:0:0:0:0:0
    • /13
    • 524 288
    • 1 024
    • 8
    • 0
    • fff8:0:0:0:0:0:0:0
    • /1210
    • 1 048 576
    • 2 048
    • 16
    • 1
    • fff0:0:0:0:0:0:0:0
    • /11
    • 2 097 152
    • 4 096
    • 32
    • 2
    • ffe0:0:0:0:0:0:0:0
    • /10
    • 4 194 304
    • 8 192
    • 64
    • 4
    • ffc0:0:0:0:0:0:0:0
    • /9
    • 8 388 608
    • 16 384
    • 128
    • 8
    • ff80:0:0:0:0:0:0:0
    • /8
    • 16 777 216
    • 32 768
    • 256
    • 16
    • ff00:0:0:0:0:0:0:0
    • /7
    • 33 554 432
    • 65 536
    • 512
    • 32
    • fe00:0:0:0:0:0:0:0
    • /6
    • 67 108 864
    • 131 072
    • 1 024
    • 64
    • fc00:0:0:0:0:0:0:0
    • /5
    • 134 217 728
    • 262 144
    • 2 048
    • 128
    • f800:0:0:0:0:0:0:0
    • /4
    • 268 435 456
    • 524 288
    • 4 096
    • 256
    • f000:0:0:0:0:0:0:0
    • /3
    • 536 870 912
    • 1 048 576
    • 8 192
    • 512
    • e000:0:0:0:0:0:0:0
    • /2
    • 1 073 741 824
    • 2 097 152
    • 16 384
    • 1 024
    • c000:0:0:0:0:0:0:0
    • /1
    • 2 147 483 648
    • 4 194 304
    • 32 768
    • 2 048
    • 8000:0:0:0:0:0:0:0
    • /0
    • 4 294 967 296
    • 8 388 608
    • 65 536
    • 4 096
    • 0:0:0:0:0:0:0:0