Today, REVIEW has a web foundation.
First, TCP / IP protocol set
Meaning IP: Internet Protocol, Internet Protocol TCP: Transmission Control Protocol, Transfer Control Protocol UDP: User DataGram Protocol, User Data News Agreement
Simple History 1975: TCP / IP Protocol Generation January 1, 1983: Facts Standards Agreement with Internet now: TCP / IP protocols are integrated into Unix, Linux, Windows, etc. TCP / IP protocols are the general name of the Internet communication protocol set, containing Hundreds of agreements, and TCP and IP itself are just two basic protocols of the agreement.
Common protocol effect IP: Provide end-to-end (machine-to-machine) Packet transfer service TCP: Working over IP, providing a reliable data transfer service. There is a connection service. UDP: Working over IP and provides unreliable user datagram. There is no connection service, not guaranteed, and it is not guaranteed to be received in order.
Several ratings than IP: Ordinary Home TCP: Telephone Services UDP: Postal Service
Second, IP address protocol
1, the composition of the IP address: IP address consists of four 8-bit binary digital domain, with a total length of 4 bytes (theoretically forms 4, 294,967,296 different IP addresses) More than 42 billion, actually much less)
2, IP address composition: network number host number network number - Identify network host number - Identify a specific host on a network
Third, IP address type
1, class A address: 1 digit (0) 7 digits 24 digits
The highest bit of the Class A address is 0, the next seven-bit completed the network ID, the remaining 24-bit binary position represents the host ID, the A class address is used for a large number of hosts. Class A addresses allow 126 networks, each network approximately 17 million hosts; the first number is 1 to 126.
127 is a special network ID, also known native network, can be used to check the TCP / IP protocol working status. If you can use the following command to check if the TCP / IP is working properly: ping 127.0.0.1
The network mask of the A class address is: 255.0.0.0
2, class B address: 2 digits (10) 14 digits 16 digits
The highest bit of the B-class address is 10, the next 14 bit complete the network ID, the remaining 16-bit binary position represents the host ID, class B address for medium to large networks. Class B address allows 16384 networks, approximately 65,000 hosts per network; the first number is 128 ~ 191.
The network mask of Class B is: 255.255.0.0 3, C address: 3 digits (110) 21 digits 8 digits
The highest bit of the Class C address is 110, the next 21 bore network ID, the remaining 8-bit binary position represents the host ID, Class C address for small local networks. Class C address allows approximately two million networks, each network has 254 hosts; the first number is from 192 to 223.
The network mask of Class C is: 255.255.255.0
4, D address: 4 digits (1110) 20
The highest bit of the D address is 1110; the first number is 224 to 239. The remaining bit is designed to design a specific group attending the client. Class D address is used for multicast. A multicast address may include 1 or more hosts, or not at all. There is no network or host bit in the multicast operation, and the packet will be transferred to the selected host subset of the network. Only hosts that registered a multicast address can receive packets. Microsoft supports D address.
5, E address
Class E: The first number is 240-247 Unequential Address: The first number is 248-254
Address Category Availability A Class 1 ~ 126B Class 128 ~ 191C Class 192 ~ 223D Class 224 ~ 239E Class 240 ~ 255A Class: NIC (Network Information Center) Class C Class: INTERNIC is responsible for North America; Enic is responsible for Europe; APNIC is responsible for Asia Pacific Class C: National Network Information Center Assignment
Network address: The IP address of the suffix is 0 represents the network address, and does not allow allocation to a host, the router follows the network address according to the destination.
Decides to transfer the next stop of the data.
Broadcast Address: The IP address of the suffix is 1 to represent the broadcast address of the specified network. It is the common address of all hosts in the network. When the information of the information is this address, the information will be sent to all hosts.
Subnet: Mask put a network containing a large number of hosts into many small networks, each small network is a subnet. More divided into a subnet number field is to pay for it. For example, a Class B IP address can accommodate 65,534 host numbers. But after you divide 6 bits long subnet fields, you can have up to 62 subnets (remove all 1 and full 0 subnet numbers). Each subnet has 10BIT host numbers, that is, there can be up to 1022 host numbers per subnet. Therefore, the total number of host numbers is 62 * 1022 = 63364. There is less than if you don't divide the net.
Fourth, IP address allocation method
IP address allocation method Static allocation - specify IP address, fixed address dynamic allocation - automatically get IP address, no fixed address [Note: The server must use static address]
Dynamic Host Configuration Protocol (DHCP): DHCP-DYNAMIC HOST Configuration Protocol Dynamic Address Assignment Work Principle: Customer / Server (Client / Server)
Server-DHCP server, IP address pool, assign client: IP address subnet mask gateway DNS server
DHCP customers, apply to the server, automatically get from the server: IP address subnet mask gateway DNS server IP address
Third, the domain name DNS (Domain Name System) DNS is a network service that identifies the computer with the name on the Internet and guarantees the host name and IP address. The domain name server uses a C / S mode. It is a server-side software that runs on the specified computer, responsible for managing and storeing a database file for host name and IP address corresponding relationship, and completing the name resolution.
• Domain name structure and composition
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- "Hostname Domain Name" multi-level structure, generally not more than five
- Subdomain. Domain type. Country Code
The subdomain name can be composed of 1 to 3 (when there is no national name, the grade domain name is composed of the multi-stage subdomain, and the subdomains at each stage are separated by a decimal point, and from left to the right by small domain Big domain order
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IP and domain name: an IP address can correspond to multiple domain names, an example: a virtual host can also correspond to multiple IP addresses, examples: load balancing host and Internet connection: special line connection, LAN connection, cable phone Co-call connection , Other (wireless internet, mobile phone, cable TV, etc.)
