The server can provide a variety of services to the outside world, and various services use different ports to provide different services. Ports in TCP/IP protocol are logical ports.

Port mapping: Computers in the intranet need port mapping to access the Internet. Port mapping can be divided into dynamic and static. Dynamic port mapping: When a computer in the intranet wants to access Sina, it will send a packet to the NAT gateway. The packet header includes the other party's IP(Sina), port and local IP and port. The NAT gateway will replace the local IP and port with its own public IP and an unused port, and will record this mapping relationship so as to forward packets in the future. Then send the data to Sina.com, Sina.com will respond after receiving the data, and send the data to the unused port of NAT gateway, and then NAT gateway will forward the data to the computer in the intranet to realize the communication between the intranet and the public network. When the connection is closed, the NAT gateway will release the port assigned to this connection so that future connections can continue to be used. Dynamic port mapping is actually the working mode of NAT gateway. Static port mapping: it is to open a fixed port on NAT gateway, and then set which I and port the data received by this port should be forwarded to. This mapping relationship will always exist whether there is a connection or not. You can let the public network take the initiative to access the computers in the intranet.

3。 Understand what port mapping is in one sentence.

Port mapping is to map a port of the IP address of the host to a machine in the LAN. When a user accesses this port of this IP, the server automatically maps the request to the corresponding LAN extension (as simple as that).

first

From Server Management Tools-Routing and Remote Access-IP Routing-General (right-click)-New Routing Protocol.

Select Network Address Translation (NAT) in the new routing protocol and determine

Looking back at IP routing, there is a network address translation (NAT).

Add a new interface in the building on the right-select the connection established by the network card.

View the Internet connection properties of network address translation. There are three projects.

General-Select the public interface connected to the Internet, and then select TCP/UDP.

Address Pool-Do not set it.

Special port-it is also very simple to use UDP protocol to correspond to fixed IP, local IP and port.

What is port mapping?

Port mapping:

Many customers ask why port mapping is needed every day. For example, if you surf the Internet through a router, the website can be accessed by yourself, but others can't; Enter 127.0.0. 1 to visit, but others still can't see it; You can see it by typing localhost, but others just can't. It's irritating ~ there's no way but to map ports.

(Router Port Mapping-This course is applicable to port mapping methods of all financial management servers, such as website servers, mail servers, server servers, monitoring servers, remote servers, Kingdee servers, VPN, ERP, ftp servers, etc. ).

Step 1: First, simply tell you what port mapping is:

Port mapping is also called port forwarding and virtual server. Different brands of routers have different names. But the operation is the same. Specific model operation examples can be viewed at.

Simple and popular explanation (which everyone likes to see):

The process of port mapping is as follows: your home is in Room 24 10 of Building B, and your friend comes to you and finds the door of the community. I don't know what floor and number you live on. Just ask the security guard at the door. The security guard told him your house number politely, so your friend found your home easily. This process is the image metaphor of the external network accessing the internal network through port mapping. My metaphor is very good and easy to understand.

The following is an explanation of a rather annoying term. I'm also annoyed about it. I'm tired of reciting it every day at school (of course, people don't want to read it, but I copied it out).

In network technology, ports have several meanings. The ports of hubs, switches and routers refer to the interfaces connecting other network devices, such as RJ-45 port and serial port.

The port mentioned here is not an I/O port of computer hardware, but a concept in the form of software.

The server can provide various services to the outside world. For example, the server can be a WEB server, an FTP server or a mail server.

Why can a server provide so many services at the same time? One of the most important aspects is that various services use different ports to provide different services, such as WEB using port 80 and FTP using port 2 1. In this way, through different ports, the computer communicates with the outside world without interfering with each other. The port we are talking about here is not a physical port, but a port in TCP/IP protocol, which is a logical port.

Port mapping: If computers in the intranet want to access the Internet to open services or receive data, they need port mapping.

Port mapping can be divided into dynamic and static. Dynamic port mapping: When a computer in the intranet wants to access Sina, it will send a packet to the NAT gateway. The packet header includes the other party's IP(Sina), port and local IP and port. The NAT gateway will replace the local IP and port with its own public IP and an unused port, and will record this mapping relationship so as to forward packets in the future. Then send the data to Sina.com, Sina.com will respond after receiving the data, and send the data to the unused port of NAT gateway, and then NAT gateway will forward the data to the computer in the intranet to realize the communication between the intranet and the public network. When the connection is closed, the NAT gateway will release the port assigned to this connection so that future connections can continue to be used.

Dynamic port mapping is actually the working mode of NAT gateway.

Static port mapping: it is to open a fixed port on NAT gateway, and then set which I and port the data received by this port should be forwarded to. This mapping relationship will always exist whether there is a connection or not. You can let the public network take the initiative to access the computers in the intranet.