ip address

Spring MVC – How to get client IP address

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In Spring framework, you can @Autowired a HttpServletRequest in any Spring managed bean directly, and later get the client’s IP address from the request headers WebUtils.java package com.mkyong.web; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Component; import javax.servlet.http.HttpServletRequest; @Component public class WebUtils { private HttpServletRequest request; @Autowired public void setRequest(HttpServletRequest request) { this.request = request; } private static String …

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CSF – How to limit the number of connections per IP address

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In the ConfigServer Security & Firewall (CSF) configuration file, update the CT_LIMIT value to limit the number of connections per IP address. This is a simple trick to prevent some types of Denial of Service (DOS) attack. Note To stop the Denial of Service (DoS) attack immediately, read this null route example. 1. /etc/csf/csf.conf SSH …

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Java and “& 0xFF” example

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Before you understand what is & 0xFF, make sure you know following stuffs : Bitwise AND operator, link. Converts hex to/from binary, and decimal to/from binary. In short, & 0xFF is used to make sure you always get the last 8 bits. Let’s see an example to convert an IP address to/from decimal number. 1. …

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How to get client Ip Address in Java

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In Java, you can use HttpServletRequest.getRemoteAddr() to get the client’s IP address that’s accessing your Java web application. import javax.servlet.http.HttpServletRequest; String ipAddress = request.getRemoteAddr(); 1. Proxy Server or Cloudflare For web application which is behind a proxy server, load balancer or the popular Cloudflare solution, you should get the client IP address via the HTTP …

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How to execute shell command from Java

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In Java, we can use ProcessBuilder or Runtime.getRuntime().exec to execute external shell command : 1. ProcessBuilder ProcessBuilder processBuilder = new ProcessBuilder(); // — Linux — // Run a shell command processBuilder.command("bash", "-c", "ls /home/mkyong/"); // Run a shell script //processBuilder.command("path/to/hello.sh"); // — Windows — // Run a command //processBuilder.command("cmd.exe", "/c", "dir C:\\Users\\mkyong"); // Run a …

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How to get Server IP address in Java

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In Java, you can use InetAddress.getLocalHost() to get the Ip Address of the current Server running the Java app. package com.mkyong; import java.net.InetAddress; import java.net.UnknownHostException; public class Test { public static void main(String[] args) { InetAddress ip; try { ip = InetAddress.getLocalHost(); System.out.println("Current IP address : " + ip.getHostAddress()); } catch (UnknownHostException e) { e.e.printStackTrace(); …

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Java IP Address (IPv4) regex examples

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This article focus on how to validate an IP address (IPv4) using regex and Apache Commons Validator. Here is the summary. IPv4 regex explanation. Java IPv4 validator, using regex. Java IPv4 validator, using commons-validator-1.7 JUnit 5 unit tests for the above IPv4 validators. IPv4 regex final version. ^(([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])(\.(?!$)|$)){4}$ # Explanation ( [0-9] # 0-9 | …

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How to set static IP address on Unix

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In Unix system like Debian, Ubuntu or Red Hat, It is possible to set a static IP address with ifconfig command. My current Debian system IP address is 10.70.0.61 mkyong:~# ifconfig eth0 Link encap:Ethernet HWaddr 00:15:17:1D:CE:2F inet addr:10.70.0.61 Bcast:10.70.3.255 Mask:255.255.252.0 I want change it to 10.70.0.66, just issue following command to set a static IP …

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