IPv4 & IPv6 Addressing

Great comparing between IPv4 and IPv6



IPv4 address
32-bit
4 Octets
8 bit an octet (8bits.8bits.8bits.8bits) = 32
8bits  = 1 byte
1 byte.1 byte.1 byte.1 byte = 4 bytes

IP Classes
Class A 1 - 126       /8
Class B 128 - 191   /16
Class C 192 - 223   /24
Class D 224 - 239 unicast and multicast
Class E 240 - 256

8 bit representation

128   64   32   16   8    4    2    1 



IPv6 shortcuts

0004:0000:0000:0000:0000:00FD:000C:0082

Every 4 Zeros can be 1 Zero

0004:0:0:0:0:00FD:000C:0082

Leading Zeros can be removed

4:0:0:0:0:FD:C:82

Double colon can be used to eliminate similar spaces 

4::FD:C82

Max 1 time Double Colon

::

BB::1

LLA   FE80 
Link Local Address (which is similar APIPA for ipv4 )

Stateless (autoconfigure)

11:22:33:44::/64
IPv6 subnet mask
the first 64 bits is Network prefix the remaining is Client or user Prefix or ID

how to determine your subnet mask
1- figure out how many users IDs need 
example : 14 users 
how many bits give 14 ?
2^4=16 

4 - 128 bits = 124 is the mask needed for 12 client IDs

11:22:33:44::/124


Auto Configure works?
it a new feature for ipv6 which creates a unique IPv6 address by utilizing the existing 48bit MAC address for physical NIC with insertion of FFFE in the middle of the MAC address

Statefull (DHCPv6)