At present, there are only a few general network operators (Telecom, Tietong, Netcom, Radio and Television), and the others are relatively small.
At present, there are many broadband operators in China, so each has its own address segment. 6 1 starts with Tietong's new IP segment, and telecommunications is generally 2XX. In addition, there are China Mobile, Netcom, Great Wall Broadband and Radio and Television Broadband.
Here are some address segments.
China-
203.095.000.000 China-
203.223.000.000 China-
203.087.224.000
China-
203.090.000.000 China-
China-
203.09 1.000.000
061.144.000.000 061.159.255.255 China-
203. 184.000.000 China-
China-
2 10.072.000.000
211.088.000.000 211.103.255.255 China-
203.192.000.000 203.196.255.255 China
China-
202.102.000.000 202.102.255.255 China 163 users.
202.090.000.000 202.127.255.255 China 163 users.
061.128.000.000 061.143.255.255 China 169 net 163 address.
010.000.000.000 010.005438+0.255.255 China 169 network center.
010.000.018.000 010.000.020.255 China 169 network center.
010.000.000.000 010.255.255 China 169 users.
203.207.064.000 China CEI (China Economic Information Network) backbone network.
203.207.065.000 China CEI (China Economic Information Network) backbone network center.
2 1 1.088.000.000
159.226.001.000159.226.003.255 China CNNIC, China Internet Information Center.
China Aauto Quicker users.
192.188.170.000192.188.170.255 Oracle Bone Inscriptions, China.
China PIPEX
202.095.252.000 202.095.255.255 China SBI &；; S
202.038.032.000 202.038.047.255 China Nortel.
202.038.151.000 202.038.151.255 China Nortel.
162.105.000.000162.105.255.255 Peking University, China
162.105.010.000105.05438+01.255 IBM Center in Peking University, China.
162.105.122.000105.122.255 China Peking University IBM Center/School Foundation.
162.105.122.000105.122.255 China Peking University IBM Center/School Foundation.
162.105.239.000162.105.239.255 China Peking University Security Office.
162.105.017.000162.105.05438+07.255 China Peking University North Pavilion/Remote Sensing Institute.
162.105.207.000162.105.207.255 China Beida Beijia/Resources Company.
162.105.228.000162.105.228.255 China Peking University finance office.
162.105.149.000162.105.149.255 China Peking University city ring system.
162.105.019.000162.105.05438+09.255 China Peking University city ring system.
162.105.188.000105.188.255 China Peking University publishing house.
162.105.232.000162.105.232.255 China Peking University Party Office/School Office/Finance Office.
162.105.023.000162.105.023.255 Peking University Department of Geophysics.
162.105.161.000162.105.5438+061.255 Peking University Geophysical Department.
162.105.180.000162.105.180.255 Geological Department of Peking University.
162.105.020.000162.105.020.255 Peking University geology department/technical physics department/geophysics department, China.
162.105.137.000162.105.137.255 China Peking University audio-visual education center.
162.105.014.000162.105.438+04.255 China Peking University audio-visual education center.
162.105.199.000162.105.199.255 Electron microscope in Peking University, China.
162.105.027.000162.105.027.255 Electronic Department of Peking University, China.
162.105.160.000162.105.160.255 Peking University electronic system.
162.105.186.000162.105.186.255 China Peking University East Language Department.
162.105.206.000162.105.206.255 Russian Language Department in Peking University, China.
162.105.148.000162.105.6438+048.255 China Peking University law department.
162.105.162.000162.105.165.255 China Peking university founder group.
162.105.123.000162.105.124.255 China Peking university founder group.
162.105.175.000162.105.175.255 China Peking university probability system.
162.105.142.000162.105.4438+042.255 China Peking University institute of higher education.
162.105.015.000162.105.438+05.255 China Peking University Hospital.
Guanghua School of Management, Peking University, China162.105.182.000
162.105.189.000162.105.189.255 China Peking University institute of international relations.
162.105.227.000162.105.227.255 China Peking University overseas education institute.
162.105.022.000162.105.022.255 Department of Chemistry, Peking University, China.
162.105.153.000162.105.153.255 Department of Chemistry, Peking University.
162.105.157.000162.105.157.255 China Peking university environmental center.
162.105.147.000162.105.6438+047.255 Ministry of Science and Technology, Peking University, China.
162.105.181.000162.105.181.255 China Peking University Computer.
162.105.179.000162.105.179.255 Computer Department of China Peking University.
162.105.170.000105.170.255 China Peking University calculation.
162.105.18.000162.105.121.255 Calculation of China Peking University.
162.105.183.000105.183.255 China Peking University calculation.
162.105.184.000105.184.255 China Peking University calculation.
162. 105.008.000 China Peking University Computing Center
162.105.192.000162.105.6438+092.255 China Peking University institute of economics.
162.105.169.000162.105.169.255 China Peking university economic center.
162.105.214.000162.105.438+04.255 Peking University Archaeological Department.
162. 105.225.000 Peking University department of archaeology
162.105.212.000162.105.438+02.255 China Peking university history department.
162.105.195.000162.105.6438+095.255 Peking University Department of Mechanics.
162.105.025.000162.105.025.255 Peking University Department of Mechanics.
162.105.194.000162.105.438+094.255 China Peking University Marxism-Leninism Institute.
162.105.202.000162.105.202.255 China Beida Jade Bird Company.
162.105.191.000162.105.438+095438+0.255 China Peking University Population Research Institute.
162.105.193.000162.105.193.255 Department of Sociology, Peking University, China
162.105.236.000162.105.236.255 China Peking University equipment office.
162.105.172.000162.105.438+072.255 China Peking University Life Center.
162.105.016.000162.105.438+06.255 Peking University biology department.
162.105.155.000 Peking University biology department.
162.105.018.000162.105.05438+08.255 Peking University Department of Mathematics/Psychology.
162.105.158.000162.105.158.255 China Peking University Institute of Mathematics.
162.105.140.000162.105.6438+0.255 China Peking university library.
162.105.138.000162.105.438+038.255 China Peking University Library.
162.105.028.000162.105.028.255 China Peking University library.
162.105.139.000105.139.255 China Peking University library/science magazine.
162.105.226.000162.105.226.255 China Peking University foreign affairs office.
162.105.201.000162.105.438+0.255 China Peking University Institute of Microelectronics.
162.105.177.000162.105.177.255 China Peking University Institute of Physiochemistry.
162.105.010.000162.105.438+0.255 Peking University Department of Physics.
162.105.159.000162.105.159.255 Peking University Department of Physics.
162.105.187.000162.105.187.255 western languages department of Peking University, China.
162.105.174.000162.105.6438+074.255 China Peking University Modern Physics Center.
162.105.46438+0.000162.105.438+0.255 China Peking University school hospital.
162.105.176.000162.105.438+076.255 Department of Psychology, Peking University.
162.105.166.000162.105.166.255 Department of Information Science, Peking University, China.
162.105.178.000162.105.178.255 China Peking university information center.
162.105.190.000105.190.255 China Peking University administration department.
162.105.032.000162.105.050.255 China Peking University Graduate Dormitory.
162.105.238.000162.105.238.255 China Peking University graduate school.
162.105.171.000162.105.5438+075438+0.255 China Peking University Institute of Remote Sensing.
162.105.185.000162.105.6438+085.255 English Department of China Peking University.
162.105.213.000162.105.438+03.255 China Peking University Language Institute.
162.105.204.000162.105.204.255 Department of Philosophy, Peking University.
162.105.205.000162.105.205.255 Chinese Department of Peking University.
162.105.31.000162.105.438+0.255 General Affairs Office of Peking University, China.
202.020.120.000 202.020.120.255 Beijing Institute of Seismology, China.
Beijing university of chemical technology, China
202.004.142.000 202.004.142.255 China beijing university of chemical technology institute of material engineering.
202.004.145.000 202.004.145.255 China beijing university of chemical technology school of management.
202.004.141.000 202.004.141.255 China beijing university of chemical technology Institute of Chemical Technology.
202.004. 143.000 China beijing university of chemical technology Institute of Mechanical Engineering.
202.004. 139.000 China beijing university of chemical technology Library
202.004. 130.000 China beijing university of chemical technology network center
202.004.146.000 202.004.146.255 department of applied chemistry, beijing university of chemical technology, China.
202.004.144.000 202.004.144.255 China beijing university of chemical technology automation department.
202.014.088.000 202.014.088.255 China Beijing computer application society (certified public accountant).
202.038.152.000 202.038.153.255 China Beijing sihuan medical information center.
202.130.224.000 202.130.255.255 China Oriental Netscape users.
168.160.000.000168.160.255.255 National Science and Technology Commission of China
203.093.000.000 China Jitong users.
203.094.000.000 China Jitong users.
210.012.000.000 210.012.063.255 China Jitong users.
210.014.224.000 210.014.255.255 China Jitong users.
202.000.110.000 202.000.110.255 China Planning and Design Center (CPDC).
202.192.000.000 202.207.255.255 China Education Network
202.038.123.000 202.038.123.255 China education network router
211.064.000.000 211.069.255.255 Users of China Education Network
210.025.000.000 210.047.255.255 Users of China Education Network
202.192.000.000 202.192.438+05.255 China education network center
203.207.192.000 203.207.223.255 Users of China Economic Information Network
203.207.124.000 203.207.159.255 Users of China Economic Information Network
159.226.000.000159.226.255.255 China academy of sciences.
210.073.000.000 210.073.05438+0.255 China academy of sciences.
211.093.000.000 211.094.255.255 China Unicom
211.088.000.000 211.093.255.255 China Unicom users.
202.097.001.000 202.097.001.255 China router (Beijing)
202.097.017.000 202.097.018.255 China router (Beijing)
202.097.009.000 202.097.010.255 China router (Beijing)
202.097.020.000 China Router (Beijing)
202.097.026.000 China Router (Beijing)
16 1.207.000.000 China Petroleum Company
211.098.000.000 211.098.6438+027.255 China Railway Telecom.
210.072.000.000 210.072.127.255 China Statistical Information Network
202. 136.252.000 China netcom
203.208.000.000 203.208.018.255 Users of China Information Industry Gold Network.
202.113.032.000 202.113.047.255 China civil aviation institute.
202.130.000.000 202.130.438+0.255 China Yinghaiwei users.
202.120.144.000 202.438+020.6438+059.255 China Textile University-
202.204.016.000 202.204.019.255 China China institute of labor and transportation-
2 10.025.000.000 China China International Electronic Commerce Center Headquarters-
China Ji Liang University, China-
210.045.232.000 210.045.233.255 China China Computer Correspondence College-
211.066.000.000 211.066.000.255 China China Education and Research Computer Network 99 Annual Meeting-
211.068.127.000 21.068.127.255 China China Education and Research Computer Network Cost Sharing Management Center-
210.045.112.000 210.045.127.255 Beijing, School of Economics and Technology, University of Science and Technology of China, China.
2 10.045.064.000 China University of Science and Technology of China-
210.033.128.000 210.033.131.255 Institute of Subtropical Forestry, China Academy of Forestry-
202.204.248.000 China Chinese Academy of Forestry.
210.033.124.000 210.033.127.255 China Academy of Art, China-
210.033.112.000 210.033.15.255 China Academy of Art, China-
210.045.000.000 210.045.015.255 China China People's Liberation Army Artillery Academy-
210.028.128.000 210.028.143.255 China China People's Liberation Army Communication Engineering College-
210.042.208.000 210.042.223.255 China People's Liberation Army Foreign Language School-
211.068.048.000 211.068.063.255 china academy of railway sciences, China-
210.047.128.000 210.047.143.255 China China Criminal Police College-
202.119.176.000 202.1191.255 China China Pharmaceutical University-
202.113.248.000 202.113.255.255 China, Institute of Radiation Medicine, China Academy of Medical Sciences-
202.118.040.000 202.118.047.255 China University of Chinese Medicine-
IP address can be divided into intranet IP and extranet IP. If you use residential broadband to surf the Internet, you can look at the properties of online neighbors. This address is fixed, and it is an intranet IP. The IP of the external network is automatically assigned by the telecom company. If you use a broadband cat to surf the Internet, the IP address is dynamic and automatically assigned.
IP address is a 32-bit binary value, which is used to mark the address of each computer in TCP/IP communication protocol. Usually we use dotted decimal system, such as 192.5438+068.438+0.6, etc. In other words, there are two representations of IP addresses: binary and dotted decimal. The binary of a 32-bit IP address contains four 8-bit fields. Namely11000000100000010000038+0000438+000438+000438+000438+00 (192
Each IP address can be divided into two parts. That is, the network number part and the host number part: the network number indicates the network segment number to which it belongs, and the host number indicates the address number of the host in the network segment. According to the size of the network, IP addresses can be divided into five categories: A, B, C, D and E, among which A, B and C are the three main types of addresses, D is the multicast address used for multicast transmission, and E is used to expand the standby address.
Class a IP address
Class A IP address consists of 1 byte network address and 3 bytes host address. The highest digit of the network address must be "0", and the address range is from 1.0.0.0 to 126.0.0. There are 126 Class A networks, and each network can accommodate more than 1 100 million hosts. It should be noted that the network number cannot be 127 because it is reserved for loop and diagnostic functions.
Class b IP address
Class B IP address consists of two bytes of network address and two bytes of host address. The highest digit of the network address must be "10", and the address range is128.0.0 to 19 1.255.255. There are 16382 Class B networks, each of which can accommodate more than 60,000 hosts.
Class c IP address
Class C IP address consists of a 3-byte network address and a 1 byte host address. The most significant bit of the network address must be "1 10". The range is from 192.0.0 to 223.255.255.255. There are more than 2.09 million Class C networks, and each network can accommodate 254 hosts.
Class d addresses are used for multicast.
The first byte of a Class D IP address begins with "lll0", which is a specially reserved address. It does not point to a specific network. At present, this address is used for multicast. Multicast address is used to address a group of computers at a time, which identifies a group of computers sharing the same protocol.
Class e IP address
Starting with "llll0" and reserved for future use, all zeros ("0.0.0.0") address corresponds to the current host; The IP address of all "1"("255.255.255.255") is the broadcast address of the current subnet.
I. IP address planning
Basic concept of 1.IP address
IP address is a 32-bit binary value, which is used to mark the address of each computer in TCP/IP communication protocol. Usually we use dotted decimal system, such as 192.5438+068.438+0.6, etc. In other words, there are two representations of IP addresses: binary and dotted decimal. The binary of a 32-bit IP address contains four 8-bit fields. Namely11000000100000010000038+0000438+000438+000438+000438+00 (192
Each IP address can be divided into two parts. That is, the network number part and the host number part: the network number indicates the network segment number to which it belongs, and the host number indicates the address number of the host in the network segment. According to the size of the network, IP addresses can be divided into five categories: A, B, C, D and E, among which A, B and C are the three main types of addresses, D is the multicast address used for multicast transmission, and E is used to expand the standby address.
Class a IP address
Class A IP address consists of 1 byte network address and 3 bytes host address. The highest digit of the network address must be "0", and the address range is from 1.0.0.0 to 126.0.0. There are 126 Class A networks, and each network can accommodate more than 1 100 million hosts. It should be noted that the network number cannot be 127 because it is reserved for loop and diagnostic functions.
Class b IP address
Class B IP address consists of two bytes of network address and two bytes of host address. The highest digit of the network address must be "10", and the address range is128.0.0 to 19 1.255.255. There are 16382 Class B networks, each of which can accommodate more than 60,000 hosts.
Class c IP address
Class C IP address consists of a 3-byte network address and a 1 byte host address. The most significant bit of the network address must be "1 10". The range is from 192.0.0 to 223.255.255.255. There are more than 2.09 million Class C networks, and each network can accommodate 254 hosts.
Class d addresses are used for multicast.
The first byte of a Class D IP address begins with "lll0", which is a specially reserved address. It does not point to a specific network. At present, this address is used for multicast. Multicast address is used to address a group of computers at a time, which identifies a group of computers sharing the same protocol.
Class e IP address
Starting with "llll0" and reserved for future use, all zeros ("0.0.0.0") address corresponds to the current host; The IP address of all "1"("255.255.255.255") is the broadcast address of the current subnet.
3.IP address information
Generally speaking, a complete IP address information should include four parts: IP address, subnet mask, default gateway and DNS. Only when they work together can we access the Internet and be accessed by computers on the Internet. It should be noted that when using static IP address to access the Internet, ISP should provide all IP address information for users.
IP address; network address
Legal IP addresses used by enterprise networks are assigned by Internet access service providers (ISP), while private IP addresses can be assigned freely by network administrators. It should be noted that the IP addresses of all computers in the network cannot be the same, otherwise IP address conflicts will occur and network communication will fail.
subnet mask
Subnet mask is a technology used in combination with IP address. It has two main functions, one is to determine the network number and host number in the factory address, and the other is to divide a large IP network into several small subnets.
Default subnet mask
The subnet mask is represented by four 24-bit bytes.
The subnet mask contains a partial locating network number with 1 and a partial locating host number with zero. Therefore, when the factory address and subnet mask are sum, the non-zero part is the network number and the zero part is the main phone number.
Because the subnet mask can determine which part of the IP address is the network number, and the subnet mask can be set manually, the network number and host number specified in the original address classification can be changed by modifying the subnet mask.
That is to say, according to actual needs, we can change the original network number of Class A address from one byte to two or three bytes by using the subnet mask of Class B or Class C address (i.e. 255.255.0 or 255.255.0), or use the subnet mask of Class C address (i.e. 255.255.0). You can also use the subnet mask of Class B address (i.e. 255.255.0.0) to change the subnet mask of Class C address from three bytes to two bytes, thus increasing the host capacity in each network and reducing the number of networks.
Variable length subnet mask
Because the part with subnet mask of 1 can be defined as the network number, by lengthening the subnet mask, the highest bit part of the mask that was originally 0 can be changed to 1, so that the part that should belong to the host number can be changed to the network number to achieve the purpose of subnet division.
It can be seen that the more bits of subnet mask, the more subnets are obtained, but the fewer hosts each subnet holds, the more IP resources are lost. This is because the network number of each subnet is 0 and the broadcast address is 1.
Default gateway
Default gateway means that if the host cannot find an available gateway, it will send the packet to the default designated gateway, which will process the packet. Sending information from one network to another must also go through a "gateway", that is, a gateway.
Therefore, only by setting the gateway IP address can TCP/IP protocol realize communication between different networks. So, what is the IP address of this enterprise network? If the legal factory address is adopted, the gateway is provided by the ISP; If a private IP address is used, the gateway is the IP address of the internal port of the proxy server or router.
Domain Name Server (domain name server)
DNS service is used to convert users' domain name requests into IP addresses. If the enterprise network does not provide DNS service, the IP address of the DNS server should be the DNS server of the ISP. If the enterprise network provides its own DNS service, then the IP address of the DNS server is the IP address of the internal DNS server.
Second, the planning of LAN IP address matters needing attention
With the increasing shortage of public IP addresses, small and medium-sized enterprises can only obtain one or several real class C IP addresses. Therefore, only private (private) IP address segments can be used in the intranet. When choosing a private (private) IP address, you should pay attention to the following points:
1. Assign a Class C IP address segment to each network segment. The IP address segment192.168.2.0-192.168.254.0 is recommended.
Because some network devices (such as broadband routers or wireless routers) or applications (such as ICS) have the function of automatically assigning IP addresses, and the default IP address pool is often located in 192. 168.0.0 and192.1.
2. You can use the subnet mask of Class C address, and you can use a variable-length subnet mask if necessary.
In general, do not use too large subnet mask, and the number of computers in each network segment should not exceed 250. The more computers in the same network segment, the greater the number of broadcast packets, the more effective bandwidth loss and the lower the network transmission efficiency.
3. Even if you choose10.0.1-10.255.254 or172.16.0.1-/kloc-. Of course, if necessary, you can use a variable-length subnet mask to appropriately increase the number of computers that can be accommodated.
4. Assign an independent IP address segment to the management VLAN of network equipment to avoid address conflict with the management IP of network equipment, thus affecting the realization of remote management. For the same reason, all servers should be divided into an independent network segment.
It should be noted that the efficiency of network transmission can be improved by not assigning different IP addresses to computers on the same network. In fact, computers in the same network are still in the same broadcast domain, and the number of broadcast packets will not decrease because of different IP addresses. Therefore, simply assigning different network segments to computers cannot achieve the purpose of dividing broadcast domains. If you want to reduce the broadcast domain, the most fundamental solution is to divide VLANs and then specify different IP segments for each VLAN.