The editor of Downcodes explains in detail the differences and connections between public IP and intranet IP. Public IP is the only Internet address in the world. It is used to identify network devices globally and can directly communicate on the Internet; while intranet IP is a private address used within the local area network. It is not globally unique and cannot directly communicate with the Internet. Communication needs to be converted through NAT technology, etc. This article will delve into the definition, characteristics, correlation, and application scenarios of public IP and intranet IP, and answer common questions to help you better understand the role of these two IP addresses in the network.
Public IP (Internet Protocol Address) refers to a globally unique IP address on the Internet and is used to uniquely identify a network device in a global network. The intranet IP is an IP address used in a local network. It is not recognized by Internet routers and therefore cannot be used directly on the Internet. The main differences include: global uniqueness, whether it can communicate directly on the Internet, the scope of the address space, and the need for specific technologies (such as NAT) to communicate on the external network. For example, the company's internal network uses the intranet IP, and external devices that want to access the company's network need to go through the company's public network IP.
The most common example of the use of intranet IP is that multiple devices in a home or company network share a public IP address. At this time, because these devices use intranet IP, they need to use Network Address Translation (NAT) technology to communicate on the public network. NAT technology allows multiple devices to share a public IP address. It can map an internal IP address to a public IP address and maintain communication continuity between devices.
Public IP addresses are allocated by the Internet Assigned Numbers Authority (IANA) and its affiliated Regional Internet Registries (RIRs) in accordance with globally unified standards. Devices with public IP addresses can directly access the Internet for data transmission and reception. Communication between them does not require forwarding by any intermediary device.
Public IP addresses are unique worldwide. This means that each public IP address can unambiguously point to a specific device or network interface on the Internet. This uniqueness ensures the correct delivery of data from source to destination.
Due to the characteristics of public IP, any device with a public IP address can be directly accessed by all other Internet users, provided there is no communication obstruction, such as firewalls or other security measures.
Public network IP resources are very limited, especially the IPv4 address space, which only has about 4.3 billion addresses. Due to the scarcity of IP address resources, they need to be obtained through strict management and allocation. With the promotion of the IPv6 protocol, the public IP address space has been greatly expanded, which has alleviated the shortage of IP addresses caused by the increase in equipment.
Intranet IP addresses refer to addresses used in private networks and not directly recognized by the global Internet. In many cases, the intranet IP address is a LAN private address assigned privately by the network administrator or automatically assigned by network equipment such as routers.
Intranet IP addresses are not unique in the global Internet. The same intranet IP address can be reused in different LANs because they are isolated and will not conflict with each other.
Since the intranet IP is not registered and allocated by the global Internet address allocation agency, it cannot communicate directly on the global Internet. Data transmission over the Internet is only possible after conversion or mapping.
For intranet addresses, there are several specific IP address blocks designated by IANA for use in private networks, and routers on the Internet will not route these addresses by default. These address blocks are large enough to meet the needs of the average business or individual user.
Although there are obvious differences in the usage methods of public IP and intranet IP, they are related to each other in the actual network architecture. Intranet IP addresses usually need to communicate with the outside world through the public IP address associated with them.
Devices in the intranet use NAT technology to communicate on the public network. Network address translation technology is a method of converting private IP addresses on the intranet to public IP addresses. The application of this technology allows multiple devices within the entire private network to share a single public IP address to communicate with other parts of the Internet, greatly saving IP address resources.
In some application scenarios, especially those that need to provide external services (such as web servers), using port mapping can allow data received from a specific port on the public network to be forwarded to a specific server on the intranet. In this way, even if the server uses an intranet IP, it can still receive requests from the Internet.
Public IP and intranet IP have different functions and roles in different network environments and application scenarios.
In corporate networks, a large number of intranet IP addresses are usually used to allocate employees' computers, office equipment, etc. For servers that need to provide external services, such as mail servers or website servers, public IPs are assigned to ensure that external users can access them.
Devices in the home network, including personal computers, mobile phones, smart home devices, etc., are usually assigned intranet IP addresses. The home broadband router uses the public IP for external use, so that devices at home can share the router's public IP for accessing the Internet through NAT technology.
In today's network technology, the use of public network IP and intranet IP are closely integrated and complement each other, forming an important part of the Internet. Proper management and configuration ensures efficient operation of the network and secure transmission of data.
1. What is the difference between public IP and intranet IP?
Public IP and intranet IP are addresses used to uniquely identify devices on the Internet. The main difference between them is their available scope and accessibility.
A public IP is a unique identifier assigned to a device by an Internet Service Provider (ISP). It can be accessed directly from the global network, enabling devices to communicate with other devices connected through the Internet. Public IPs are usually limited resources and require payment.
Intranet IP is an IP address used in a local area network or private network. They are assigned on the router or network device and are only visible and accessible within the LAN. Intranet IP addresses are often used to connect multiple devices, such as computers, mobile phones, and smart home devices, so that they can communicate securely within a local area network.
2. How to obtain public IP and intranet IP?
Obtaining a public IP usually requires signing a contract with an Internet Service Provider (ISP) and applying according to their requirements. Your ISP will provide your device with a unique public IP address so that your device can communicate on the Internet.
Obtaining an intranet IP is relatively simple. You only need to connect the device to a router in a LAN or private network. The router will automatically assign an intranet IP address to your device. You can find the internal IP address in the device's network settings, usually in "Network Settings" or "IP Settings".
3. Why does the device need public IP and intranet IP?
The device requires public IP and intranet IP to achieve Internet connection and LAN communication.
Public IP allows the device to communicate with other devices on the Internet, such as browsing the web, sending emails, making video calls, etc. The public IP is the unique identifier of the device globally, through which you can directly access the device.
Intranet IP allows devices to communicate within the LAN. A LAN is a group of devices connected together through a router or switch. The intranet IP address allows devices to identify each other and transmit data in the LAN, such as sharing files, printer sharing, LAN games, etc.
In short, public network IP and intranet IP are necessary conditions for devices to communicate on the Internet and LAN. They have different uses and scopes, but they all play a key role.
I hope that the explanation by the editor of Downcodes can help you understand the concepts and applications of public IP and intranet IP. If you have any questions, please feel free to ask!