Programmer Think

A simple port scanner written by python, Python environment 3.7.0, windows system Scanning whether the specified port is open for a given hostTCP connection scanning uses three handshakes of TCP to determine whether the host port is open or not. After confirming that the host port is open, send a message to the port, receive the message retu ...

1. Write a server-side program to read a set of integers sent by the client, which is represented as a string separated by spaces between a set of numbers. After sorting these integers, the corresponding string is returned to the client. If the data format is incorrect, the error message is returned, an ...

When the kernel TCP receives the SYN message, it matches the socket in LISTEN state locally to shake hands according to the destination IP and Port of the message. listen socket lookup prior to version 4.17 The current listener hashtable is hashed by port only. When a process is listening at many IP addresses with the same port (e.g.[IP1]:443, ...

First, basic concepts Before sharing BIO, let's figure out what is blocking/non-blocking and what is synchronous/non-synchronous. 1. Blocking/non-blocking: IO read blocking between the kernel (memory) and threads (applications in JVM). 2. Sync ...

Socket Sockets are an abstraction layer through which applications can send or receive data, open, read, write, and close like files.Sockets allow applications to plug I/O into the network and communicate with other applications on the network.A network socket is a combination of IP addresses and ports. Development: Sockets were originally a ...

I. Preface Crash problems may arise in our applications during daily development or testing. We should adopt a zero tolerance attitude towards such problems, because if such problems occur online, it will seriously affect the user's experience. If Crash happens to be in the process of development, developers can locate the cause of the problem ...

Leader receives client requests by starting Leader Zoo Keeper Server. First, we look at the definition of its processing chain. From the source code, we can see that the sequence of the processing chain of LeaderZoo Keeper Server is as follows:   LeaderRequestProcessor: Leader call chain begins PrepRequest Processor: Write action prepar ...

Links to the original text: https://my.oschina.net/u/1781072/blog/542608 1. Download and add Netty framework to the project 1.Netty's packages can be accessed from Netty's official ...

This article goes on to cover the rest of the server class in the first two articles. Let's first look at the server code. /** * Created by chenhao on 2019/9/4. */ public final class SimpleServer { public static void main(String[] args) throws Exception { EventLoopGroup bossGroup = new NioEventLoopGroup(1); Even ...

Today, let's introduce the Linux ss command. ss is the abbreviation of Socket Statistics, which is used to count the related information of socket connection. It is similar to netstat, but it has more powerful statistical function than netstat and can display more detailed connection information. It may be difficult to get started with SS comma ...