A, IPV4
1, ipv4 address is 32 bits long, in dotted decimal notation, four-bit binary number.
(1) A class: for large networks
Most significant bit is 0 [far left]
0xxxxxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx
Address range: 0.0.0.0-127.255.255.255
(2) Category B: used for medium-sized networks
The first two are 10
10xxxxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx
Address range: 128.0.0.0-191.255.255.255
(3) Class C: for small networks
The top three is 110
110xxxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx
Address range is: 192.0.0.0-233.255.255.255
(4) Class D Multicast: 1110
(5) E class reservation: 1111
2. Private IP: use the LAN, there is free:
Class A: 10.0.0.0-10.255.255.255
Class B: 172.16.0.0-172.31.255.255
Class C: 192.168.0.0-192.168.255.255
3, subnet mask, there are two ways of representation:
（1）ip：192.168.1.3
mask：255.255.255.0
（2）192.168.1.3/24
Remarks: ip is the network's first 24-bit bit after 8 bit is the host. 24 before the same ip address is the same subnet.
4,192.168.1.3 / 24/24 explanations:
24 refers to a 24 binary 1, binary mask is represented: 11111111.11111111.11111111.00000000, namely 255.255.255.0 to decimal
5, abnormal IPV4 format is:
（1）172.168.2.256
（2）172.168.2.2/33
This is the network itself 6,0.0.0.0
7,255.255.255.255 is a broadcast address
Two, IPV6
1, ipv6 128-bit long addresses, in the form of four hexadecimal number expressed in hexadecimal eight groups each, with intermediate ":" separated, each section is 16 bits.
2, the prefix length (subnet mask not call now) represents only one form:
（1）234e:0:4567::3d/64
Remarks: ip is the network former 64 bits, the 64-bit host. 64 before the same ip address is the same subnet. IPV6 default prefix is 64.
3, ipv6 notation:
(1) IPV6 run using the hexadecimal notation, the format X: X: X: X: X: X: X: X, where each X represents address 16b, in hexadecimal,
E.g:
2001:0DB8:0000:0023:0008:0800:200C:417A
→ 2001: DB8: 0: 23: 8: 800: 200C: 417A (the leading 0 each X may be omitted)
(2) IPV6 compressed representation using 0, in some cases, an IPv6 address may contain intermediate long 0, 0 can be compressed to a contiguous stretch "::."
However, in order to ensure the uniqueness of address resolution, address "::" can only appear once,
E.g:
FF01: 0: 0: 0: 0: 0: 0: 1101
→ FF01 :: 1101
0:0:0:0:0:0:0:1
→ ::1
0:0:0:0:0:0:0:0
→ ::
(3) IPV6 IPV4 addresses using embedded representation, in order to achieve intercommunication IPv4-IPv6, the IPv4 address is embedded in the IPv6 address, in which case the address is often represented as:
X: X: X: X: X: X: dddd, before taking 96b using its hexadecimal representation, 32b and the last address is an IPv4 dotted decimal notation.
E.g:
:: 192.168.0.1 and :: FFFF: 192.168.0.1 are two typical examples.