ports and protocols

Main Command: lsof netstat Netstat-anpt | grep PID After knowing the process number, you can use this method to view which network ports are being used by the current process Run the lsof command to view the files opened by the process. Lsof-P 2012 // What files are opened by a process whose process number is 2012 (all files in Linux). Generally, a server such as JBoss can see that it has opened many files. Lsof-C Apache // files opened by th

different types of service, with ports divided into two types, TCP ports and UDP ports. Computer communication between the time, divided into two ways: one is to send information, you can confirm the arrival of information, that is, the answer is the way, most of the use of TCP protocol; One is sent after the no matter, not to confirm the arrival of information,

first, the basic concept Lan:local Area Network's abbreviation, i.e. LANour computers and our routes are connected to this port . Wan:wide Area network abbreviation, the WANthe network cable that the operator pulls in is connected to the mouth. The Chinese name of the VLAN (virtual local area network) isVLANs are typically subdivided into several network segments logically in a local area network to form a VLAN. A local area network can be divided into more than n VLANs, so that VLANs cannot co

through the port.Why do you need the concept of ports? In the process of network communication, you need to uniquely identify the endpoints on both ends of the communication, that is, using ports to identify applications running on a host. If no port is introduced, it can only be identified by the process number. Process numbers are dynamically allocated by the system, and different systems use different p

1. Check if the server port is occupied>lsof-i:80812. View all ports on the server>netstat-ntlp3. Check if the server is open for a portTCP port: >NETSTAT-NTPLUDP port: >NETSTAT-NUPLCommon parameters:-A (All) displays all options and does not show listen related by default-T (TCP) displays only TCP-related options-U (UDP) displays only UDP-related options-N refuses to display aliases, showing all numbers converted to numbers.-l list only service statu

/system32/Drivers/etcDirectoryProtoclAndServeisFile to view more protocol ports A socket is a combination of an IP address and a TCP port or a UDP port. The IP address component of the socket helps identify and locate the target computer. The port determines the specific application to which data is delivered. 4) Application Layer It contains many complex protocols and is the most complex layer.

This article Reprinted from: http://www.ruanyifeng.com/blog/2012/05/internet_protocol_suite_part_ I .html We use the Internet every day. Have you ever wondered how it is implemented? Billions of computers around the world are connected together and communicate with each other. One Network Card in Shanghai sends a signal, and the other network card in Los Angeles actually receives the signal. The two actually do not know the physical location of the other. Do you think this is amazing? The core

We use the Internet every day. Have you ever wondered how it is implemented? Billions of computers around the world are connected together and communicate with each other. One Network Card in Shanghai sends a signal, and the other network card in Los Angeles actually receives the signal. The two actually do not know the physical location of the other. Do you think this is amazing? The core of the Internet is a series of protocols, called Internet

1024 The following is reserved for the system, and from 1024-65535 is used by the userFor personal writing applications, try not to use a port number between 0 and 1024.1024 to 65535 we can program with. This is not a Linux rule, it is the socket rules.1, 0~1023, these ports have IANA allocation and control, if possible, the same port number is assigned to TCP, UDP and SCTP the same given service. such as the 80 port is given to the Web service2.1024~

Before we talk about routing protocols, let's look at the structure of the routers:A router is a dedicated computer with multiple input ports and multiple output ports whose task is to forward groupings.The core of the routing part is the routing processor, which can construct a way out of the table according to the selected routing protocol, and Exchange routing

This article describes the basic working principles of routers in TCP/IP networks and introduces several functions of IP routers, the static and dynamic routing protocols, as well as the concepts of the internal gateway protocol and the external gateway protocol are given, at the same time, the most common RIP, OSPF, BGP and BGP-4 routing protocols are briefly introduced, and then the design objectives and

HTTP proxies are the most classic and most common proxy protocols. Its use is very extensive, commonly seen in the company intranet environment, the General staff need to configure an HTTP proxy browser to access the Internet. At first, HTTP proxies were also used to climb g*w, but because the g*w was evolving, ordinary HTTP proxies had long been invalidated. However, there are still many people using plaintext HTTP proxy protocol combined with softwa

We use the Internet every day. Have you ever wondered how it is implemented? Billions of computers around the world are connected together and communicate with each other. One Network Card in Shanghai sends a signal, and the other network card in Los Angeles actually receives the signal. The two actually do not know the physical location of the other. Do you think this is amazing? The core of the Internet is a series of protocols, called Internet Prot

I. Overview 1.1 Five-layer model The realization of the Internet, divided into several layers. Each layer has its own function, like a building, each layer is supported by the next layer. What the user touches is just the top layer, and there is no sense of the layer below. To understand the Internet, you must start from the bottom and understand the function of each layer. There are different models for layering, and some models are divided into seven layers and some four layers. I think it

The ports and protocols used by the Samba service:1) Port 137 (UDP)-NetBIOS name service; NMBD2) port 138 (UDP)-NetBIOS Datagram Service 3) port 139 (TCP)-File and print sharing, SMBD (SMB (Server Message Block) protocol, mainly used on LAN, file sharing protocol) 4) port 3 (TCP)-for LDAP (Active Directory Mode) 5) port 445 (TCP)-NetBIOS service uses this port in WinDOS 2000 and later versions (Common Inter

the message as a response, as shown in the following figure. Each network application has its own application-layer protocol, which defines the format and sequence of messages exchanged between processes, as well as actions taken when sending or receiving messages. 　　Figure 1: Communication with each other should be with The application layer is a good place for us to start studying the agreement. We are already familiar with many applications that rely on

-232, RS-422 and RS-485 standards only to interface electrical characteristics to make provisions, and does not involve connectors, cables or protocols, on this basis, users can establish their own high-level communication protocols. The most frequently used plug-ins we encounter in our actual work have three DB9 DB25 RJ45 plug-ins. The above three plug-ins can be used as serial port plug-ins, you can also

I. Summary This article compares the transmission performance of five communication protocols, including RMI, Hessian, burlap, httpinvoker, and Web Service, in different data structures and data volumes. RMI is a remote communication protocol provided by the Java language. It is stable and efficient and is the basis of EJB. But it can only be used in Java Program Communication. Hessian and burlap are open source