Internet access knowledge

Knowledge about Internet access to the Intranet 1. the gateway or router does not intercept information sent from the internal network, but identifies and filters information sent from the external network, it is considered safe and valid before it is forwarded to the Intranet computer. This is the case that many Intranet BT users do not have "remote" and the speed is not satisfactory. 2. Port ing: Port ing is required for an intranet computer to open services or receive data on the Internet. Port ing is divided into dynamic and static. dynamic port ing: if a computer in the Intranet needs to access xinlang, it will send packets to the NAT gateway, including the IP address, port, and local IP address and port of the Peer (I .e. xinlang, the NAT gateway will replace the local IP address and port with its own public IP address and an unused port, and write down the ing relationship for future packet forwarding. Then, send the data to Sina. Upon receiving the data, Sina responds and sends the data to the unused port of the NAT Gateway. Then, the NAT Gateway forwards the data to the computer on the Intranet, implement communication between the Intranet and the Internet. when the connection is closed, the NAT Gateway releases the port allocated to the connection so that future connections can continue to be used. Dynamic port ing is actually how NAT Gateway works. Static port ing: a fixed port is opened on the NAT gateway, and the data received by the port is set to which IP address and port to forward to the Intranet, whether or not there is a connection, this ing will always exist. You can allow the public network to actively access a computer on the Intranet. 3. There are two ways to check whether your machine is an intranet address or an Internet address: 1. Check the IP address of your machine. If it is 192.168.x.x or 10.48.x.x, it is generally an intranet address. 2: visit this URL: http://www.ip138.com/ Check whether the address on the webpage is the same as the address on your machine. If it is different, it means that you are in the intranet. If you use a vro to access the Internet, you must have an intranet address. 4. VPN: Virtual Private Network. The Virtual Private Network is like A: A of A department of Company A wants to send A letter to B of A Department of Company B. A knows the address and Department of B, but the name of the Department cannot be indicated in the letter between the company and the company. Therefore, A asks his secretary to put the letter (A can choose whether to use the password to communicate with B) from the designated department B in the large envelope sent to Company B's address. When the secretary of Company B receives a letter from Company A sent to Company B, the Secretary will send the letter from the designated department placed in the large envelope to Company B via internal mail. Similarly, B will reply to A in the same way. 5. In Windows Port ing, due to limited public IP addresses, Many ISPs use multiple Intranet users to share a public IP over the INTERNET through proxy and gateway routing, in this way, these users are restricted from setting up personal websites on their own computers. To implement these websites, the most important thing is, how can I map the Intranet IP addresses of multiple users to the IP address that they only share the Internet!