Linux socket uses a 16-bit unsigned integer to indicate the port number. The maximum value is 65535. There is a classic misunderstanding about the port number. Because the port number is limited, a client can establish a maximum of 65536 socket connections, but this is not the case. The port can be reused.
A socket connection is a four-tuple consisting of [srcip, srcport, destip, destport]. If the Protocol (TCP, UDP, rawsocket, etc.) is a quintuple, In this four-tuple, as long as one element is
How to check and use serial ports under Linux
How do I check and configure serial ports under Linux for various purposes such as modem, null ing nullModems or connect a dumb terminal?Linux offers various tools. Linux uses ttysx for a serial port device name. For example, COM1 (DOS/Windows Name) is ttys0, com2 is ttys1 and so on.Task: Display detected system's serial support
Simple run dmesg command$ dmesg
Execute shell commands in the program to automatically obtain all online IP addresses and open ports in the LAN (Linux)Preface
The question is a bit long. It is actually the following: first, let the Shell command be executed in the program, and then pass the execution result to the variable, so that subsequent transactions can be processed, the second is to use the nmap command to obtain all the online IP addresses and open
8080,tomcat app using 8090), and each server farm sets the URL rewrite routing rules rule, The rules are forwarded to different serverfarm processing according to the different access URLs.Scenario one uses a different domain name to accessAn app domain name under IIS is Www.iisproject.com, and one of the app domain names under Tomcat is www.tomcatproject.com.Routing rules used by Iisfarm.According to the settings, only HTTP requests for 80 ports und
Completely solve the problem of insufficient TCP client ports [problem] when making large concurrent performance calls at www.2cto.com, we often encounter a problem: the client port is exhausted. [Cause] after analysis, the main cause is that there will be a timewait time after the connection is disconnected and the socket ,...
Completely solve the problem of insufficient TCP client ports [problem] when mak
View port
To view the port in Windows 2000/XP/Server 2003, run the netstat command:
Click Start> Run, type cmd, and press enter to open the Command Prompt window. Type "netstat-a-n" in the command prompt. Press the Enter key to view the TCP and UDP connection port numbers and statuses displayed in numbers.
TIPS: netstat command usageCommand Format: netstat-a-e-n-o-s
-A indicates that all active TCP connections and TCP and UDP ports listened by th
Resolve Chorme Error 312 (net::err_unsafe_port) issuesIn the development, sometimes we will give Tomcat and so on some special access ports, such as 8888,66666,99999 and so onIf accessed with Chorme, the error will be as follows: The current solution is:Add this string to your Chorme shortcut--explicitly-allowed-ports=xxxXXXX is your port number.For example, if you want to turn on the 8888 port number, the
A description of the application scenarioDo you have this? A requirement: The number of ports used by Java programs on many servers is compared with the normal values.You can use the following command to get the result:Netstat-tulnp|grep java|wc-lBut a lot of servers, each manual to execute this command is not realistic. So think of using ansible batch to execute, ansible use Paramiko to SSH login server execute command, and use mutilprocessing to imp
Under Linux, by default 1024 of the following ports are to be used under the root, under other users, if the attempt to use will be an error. At some point, we may consider that the program runs under the root account, but this may pose a security risk to the Linux system. How is it possible for a non-root user to enable a program that is less than 1024 open to the outside?This article attempts to give some methods:The first method: SetUIDGiving the u
Introduction: In a Linux server, it is often necessary to see whether certain ports on the system are open properly, or to know which processes occupy a particular port service, so this command is very common, and this article describes the common methods of these commands.1. See if a particular port is turned on or occupiedList all the TCP connections in the Listening state:Command parsing:-l list all listening p
This tutorial is currently the safest tutorial, if you are novice please follow the steps of the tutorial strictly, if there is a certain basis for people can selectively skip certain paragraphs modify port configuration
Run first
Vim/etc/ssh/sshd_config
Find #port 22 and remove the previous comment, then add a line of Port 1234 below.
Port
Port 1234
Many tutorials are directly modified 22 for other ports, it is best not to do so, in case the m
open TCP22 port for remote management of the system.
TCP23: Is the port used by Telnet, in the Windows command prompt to use the "telnet+ Server ip+ Port" way to enter the port corresponding to the remote host, for example, Telnet pop.qq.com 110 Port After you can enter the corresponding command to operate the mail in the mailbox, this command is often used to test whether the host open the corresponding port, if not a meeting to indicate that the connection failed.
TCP25: Dedicated to the SM
In the previous post, "Installing, Deploying DPM 2010 Server," We went to work with you on how to complete the installation of DPM, posting today, mainly to chat with you about the DPM 2010 installation process, which ports we need to open, here, We use Group Policy to introduce how to open ports for DPM, and, of course, you can have the policy of opening ports f
Tags: ports boot failure firewalld file enabled BLE Basic use shutdown firewall stop1, the basic use of the FIREWALLD start: Systemctl start Firewalld view state: Systemctl status Firewalld stop: Systemctl disable FIREWALLD disabled: systemct L Stop Firewalld 2.systemctl is the primary tool in the CENTOS7 Service Management tool that incorporates the functionality of the previous services and Chkconfig.Start a service: Systemctl start Firewalld.servic
Because smart switching performs simultaneous data exchange on most ports, it requires a wide switching bus bandwidth. If a layer-2 switch has N ports, multiple Access ports and low prices provide a perfect solution for small network users.
In order to ensure the key services of users and treat users of different levels differently, a broadband IP network is requ
The Ethernet port has three link types: Access Hybrid and Trunk. An Access port can belong to only one VLAN and is generally used to connect to a computer. A Trunk port can belong to multiple VLANs and receive and send packets from multiple VLANs, it is generally used for ports connected between switches. Hybrid ports can belong to multiple VLANs and can receive and send packets from multiple VLANs, it can
Currently, the most common Trojan Horse is based on the TCP/UDP protocol for communication between the client and the server. Since the two protocols are used, it is inevitable to open the listening port on the server side (that is, the machine where the trojan is planted) to wait for the connection. For example, the monitoring port used by the famous glaciers is 7626, And the Back Orifice 2000 is 54320. Then, we can check whether a trojan or other hacker program has been planted by checking the
In linux, apache provides an in-depth description of how to configure virtual hosts with multiple ports. By default, the default document directory used by apache in linux is: varwww default port is: 80. if you want to publish your own system resource directory, you can use the following method, run
The default document directory is/var/www.
Default Port: 80
To publish a System Resource Directory, run the following command:
(1) add a listening port#
Configuring multiple sites on different ports: php + apache + mysql
The configuration of multiple sites with different ports is as follows (only modified in http. conf)
NameVirtualHost *: 80
NameVirtualHost *: 81
NameVirtualHost *: 82
# 1st websites are used to run company websites
DocumentRoot "D:/myweb /"
ServerName oa
Php_value include_path ".; D:/myweb"
# 2nd websites are used to run OA
Docume
this re-encapsulation, it is then forwarded to the access switch of the building.
Look at the last feature: A Bridge is a storage and forwarding device used to connect to a similar LAN. These bridges listen to each transmitted data frame on all ports and use the bridge table as the basis for forwarding the data frame. The bridge table is a MAC address and a "MAC address-port number" list used to reach the address. It refresh the source MAC address of
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