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Introduction to FTP protocol: FTP protocol is a file transfer protocol, which acts on the application layer. Its function is to realize the file transfer between the server and the client (C/S architecture). The transmission uses the plaintext transmission of TCP connection (command channel and data flow channel). FTP protocol needs two TCP ha ...

1: Filter chain Multiple Filter programs can be registered in a Web application, and each Filter program can intercept a URL. If multiple Filter programs intercept the same URL, these filters will form a Filter chain (also known as Filter chain). The Filter chain is represented by the FilterChain object. There is a doFilter () method in the Fi ...

Description of experimental environment Host systemSystem versionIP addressServerLinuxRHEL 7.0192.168.43.128/24clientLinuxRHEL 7.4192.168.43.15/24clientWindows 11Windows 11192.168.43.1/24 Basic environment configuration reference [DHCP service setup] and [Samba service setup] IP address configurationYUM warehouse configuration ...

In the communication between Server and Client, data packet loss is likely to occur due to network and other reasons. If the data is missing and the information received by the Server is incomplete, it will cause confusion. We need to establish a communication protocol between Server and Client to judge whether the currently received informati ...

1, Background Traditional call making process: A calls B and invites B to establish an invitePhone B rings and phone A can hear the ringPhone B indicates a reply, so the call is establishedOn the phone...Either party hangs up and the call ends The traditional telephone uses electromagnetic wave to transmit communication signals, but at this ...

Environmental preparationClick to check whether ELK is compatible with the operating systemClick to view the list of compatibility information between ELK and JDKAlthough the official website said that ES 7.12 supports JDK8, the actual test found that ES 7.12 needs at least JDK11 or above.Therefore, it is best for our server to use the long-ter ...

Background: One OA system of the company is a stand-alone server. Due to disk failure, some OA accessories are lost. In order to avoid this problem, it is planned to realize the file spare parts function through rsync+inotify software and back up the accessories to other servers; 1, Environment introduction Source side (server that needs to sy ...

1. Basic concepts 1.1. Static web 1.2 dynamic web 2. web server lISTomcat 3,Tomcat The default port number of tomcat is 8080mysql: 3306http: 80https: 443 4,Http 4.1 concept Http: (Hypertext Transfer Protocol) is a simple request response protocol, which usually runs on TCP; port: 80Https: Secure Hypertext transmission protocol; Port: 4 ...

Linux Log System The rsyslogd daemon can receive both user process output logs and kernel logs. The user process generates the system log by calling the syslog function. This function outputs the log to a UNIX local domain socket type (AF_UNIX) file / dev/log, and rsyslogd listens to the file to obtain the output of the user process. The kern ...

DNS:Domain Name Service, domain name resolution serviceListening port: udp/53, tcp/53Application: bindRoot domain:Primary domain:Organization domain: com, .org, .net, .mil, .edu, .gov, .info, .cc, .me, .tvCountry domain: cn, .us, .uk, .jp, .tw, .hk, .iq, .irReverse domain: in-addr.arpaDNS record type: the DNS domain name database consists of re ...