Friends who often go online should know what the TCP.IP protocol is, but few people can really understand this function. I don't know what this is, and how to use it. In fact, it is generally said that the TCP/IP protocol (Transmission Control Protocol/Internet Protocol) TCP/IP protocol set establishes the technical foundation of the Internet. The full name is TransmissionControlProtocol/InternetProtocol. The Chinese translation is called Transmission Control Protocol/Internet Protocol, also known as Network Communication Protocol. It is the most basic protocol of the Internet and the foundation of the Internet International Internet. It consists of the IP protocol of the network layer and the TCP protocol of the transport layer. TCP/IP defines the standard for how electronic devices connect to the Internet and how data is transmitted between them. The protocol uses a four-layer hierarchy, with each layer calling the network provided by its next layer to fulfill its needs. In general: TCP is responsible for discovering transmission problems and signaling when there is a problem, requiring retransmission until all data is safely and correctly transmitted to the destination. IP is an address for every computer on the Internet. Diagnosing TCPIP protocol network failures can be frustrating, but it is also fun. Traditional TCPIP protocol network failures have been generally understood, but another method—structured methods—is not well understood. Below, let's take a look at the way to diagnose it. In general, the method of structured diagnosis of TCPIP protocol network failure consists of three key parts: 1. Diagnostic failure measures (1) Verify the connectivity of the client and server routing to use ping, pathping, tracert, or the like. Tools to verify end-to-end TCPIP connectivity at the network layer; packet sniffing to monitor transport layer sessions; use nslookup, telnet and other tools to diagnose domain name resolution issues. Application layer issues such as authentication. (2) Verify the relevant client. Check the cable for the physical media of the server and network architecture hardware, make sure the network adapter is properly installed, and look it up further. Verify that the network connection for the media disconnect status can be displayed. (3) Verify the relevant client. server. TCPIP protocol configuration for network architecture hardware On the client side this means checking the IP address. Subnet mask. Default gateway. DNS settings and more. For network architecture hardware, it refers to the routing table and Internet gateway on the router. Second, several aspects of the symbolic information: error messages on the client machine, login dialogs and so on. Period: continuous. Intermittent, or occasional, when to start. The type of connection in which the problem occurred: the physical layer. Network layer. The transport layer is also the application layer? Authentication or access control and so on. Network in between: cable (if not wireless). Hub. switch. router. Firewall. The proxy server, as well as other network architectures between the client and the server. Scope: One or more related client/server side. Client: The client that has the problem Server: A server that the client cannot access. Printer or other network resources (such as the Internet). Environment: External conditions that may affect your network, such as power fluctuations. Maintenance of buildings and so on. III. Understanding and Methods (1) Understanding how the protocol works Successful TCPIP protocol network fault diagnosis is based on understanding how TCPIP works and related testing tools. How packets are forwarded by the routing table, tools such as netdiag.exe can tell you what is critical. If you never try to understand the tracking mode of Network Monitor, you will have difficulty diagnosing certain problems. (2) Asking some appropriate questions is critical to troubleshooting. When to learn when to step by step, when to jump to the subject is the essence of the art of fault diagnosis. This includes fully using your left and right brains, that is, having sufficient Imagination and meticulous thinking. (3) steadily testing and isolating problems Toolboxes that require troubleshooting, and there is nothing more than a wealth of experience to help you solve complex problems. The above mainly introduces another method for detailed TCPIP protocol and network fault diagnosis.