concept
Connecting two computers on a network communicating with each other, there is some additional information in their transmitted packets, which is the address of the computer of the computer and the address of the computer that accepts data. When there is a communication based on the IP protocol, the address of these sends and accept data is an IP address.
Basic address format
The current IP network uses a 32-bit address to represent a decimal decade, such as 172.16.0.0. The address format is: IP address = network address host address or IP address = host address subnet address host address.
IP address type
When designing the internet network, each IP address includes two identification codes (IDs), namely network IDs, and host IDs for ease of addressing and hierarchical construction networks. All hosts on the same physical network use the same network ID, a host (including network workstations, servers, routers, etc.) on the network corresponds to it. The IP address is divided into five types, Class C class addresses, Class C addresses, D-class addresses, and E-class addresses depending on the different network ID.
1. Class A IP address
A Class A IP address consists of 1 byte network address and 3-byte host address, the highest bit of the network address must be "0", and the address range from 1.0.0.0 to 126.0.0.0. A available Class A network has 126, each network can accommodate more than 100 million hosts.
2. Class B IP address
A Class B IP address consists of 2 bytes of network addresses and 2 bytes of host addresses, and the highest bit of network addresses must be "10" and address ranges from 128.0.0.0 to 191.255.255.255. Available B networks have 16382, each network can accommodate more than 60,000 hosts.
3. Class C IP address
A Class C IP address consists of 3 bytes of network addresses and 1 bytes of host addresses, and the highest bit of the network address must be "110". The range was from 192.0.0.0 to 223.255.255.255. Class C networks can reach more than 209,000, each network can accommodate 254 hosts.
4. Class D address is used for multicast.
The first byte of the D IP address starts with "LLL0", which is a specially reserved address. It does not point to a specific network, and this class address is currently used in multicast. Multipoint broadcast addresses are used to address a set of computers, and it identifies a group of computers to share the same protocol.
5. E IP address
Start with "LLLL0" and reserved for future use.
Full zero ("0.0.0.0") address corresponds to the current host. The "1" IP address ("255.255.255.255") is the broadcast address of the current subnet.
In the three main types of IP addresses, each of the three areas have been reserved as a private address, and its address range is as follows:
Class A address: 10.0.0.0 ~ 10.255.255.255
Class B Address: 172.16.0.0 ~ 172.31.255.255
Class C Address: 192.168.0.0 ~ 192.168.255.255
[Friendly Tips: If your address is private address, then congratulations, you are the internal network user, you can't use some software that needs public IP]
Subnet mask
The subnet mask is a 32-bit 2 credit address for quick determination of which of the IP address represents the network number, the part identifies the host number, determined whether the 2 IP addresses belong to the same network, which produces a subnet mask The subnet mask is given in accordance with the IP address format, the subnet mask of the A, B, and C is as follows
A: 255.0.0.0
B: 255.255.0.0
C: 255.255.255.0
Such as: 10.65.96.1 is a class IP, so the default subnet mask is
255.0.0.0
E.g
202.10.138.6 and 202.10.138.95 are IPs of Class C
So the mask is
255.255.255.0
After the operation is calculated, the network number is obtained, indicating that the host is located in the same network.
Another use of the subnet mask is the division subnet. In the actual camp, there is often a problem that the network number is not enough, and some 2-based bits of the host number identification section need to be marked.
Dynamic and non-dynamic IP
The host IP of the network has a fixed and dynamic IP division, for some organizations with Internet services
Such as information port, developed the server of [WWW, FTP, TELNET, E-mail], which usually needs to announce a fixed IP, which is convenient for users to access.
These institutions tend to have a special line access, and IP is fixed. For users who dial-up Internet access [including ADSL dial], a very waste of IP resources is provided for each person due to the non-fixed time and space of the Internet.
So these users want to dial into their ISP DHCP server [will get an unfixed IP]
Of course there is a scope limit.
In each of its connection time, it is fixed rather than at any time, and the IP obtained by any two connection is not repetitive.
Query IP
View your own IP can use the following method
Use "Run" in Win98 and enter "WiniPCFG"
The IP address, gateway, subnet mask, etc.
For NT users, you can use ipconfig under CMD to view
[You can also view IP with NetStat -an]
