Use the following code to block and unblock Internet connectivity on a user’s PC:

using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;using System.Diagnostics;using System.IO;using System.Reflection;namespace BlockInternet{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        private void button1_Click(object sender, EventArgs e)        {            //ADDED A REFERENCE TO SYSTEM.SERVICEPROCESS VIA PROJECT->ADD REFERENCE, .NET tab            System.ServiceProcess.ServiceController scPAServ = new System.ServiceProcess.ServiceController("PolicyAgent"); //IPSec            if (scPAServ.Status != System.ServiceProcess.ServiceControllerStatus.Running)            {                scPAServ.Start(); //Start If Not Running            }            string[] strCommands =  { @"-w REG -p ""Firewall"" -r ""Block All"" -f *:*:*+*:*:* -n BLOCK -x" ,                            @"-w REG -p ""Firewall"" -r ""Allow LAN"" -f 0:*:*+192.168.10.*:*:* -n PASS -x" ,                            @"-w REG -p ""Firewall"" -r ""DNS"" -f 0:*:UDP+223.211.190.23:53:UDP 0:*:UDP+223.211.190.24:53:UDP 0:*:TCP+223.211.190.23:53:TCP 0:*:TCP+223.211.190.24:53:TCP -n PASS -x" ,                            @"-w REG -p ""Firewall"" -r ""POP3"" -f 0:*:TCP+*:110:TCP -n PASS -x" ,                            @"-w REG -p ""Firewall"" -r ""POP3S"" -f 0:*:TCP+*:995:TCP -n PASS -x" ,                            @"-w REG -p ""Firewall"" -r ""FTP Control"" -f 0:*:TCP+*:21:TCP -n PASS -x" ,                            @"-w REG -p ""Firewall"" -r ""FTP Data"" -f 0:*:TCP+*:20:TCP -n PASS -x" ,                            @"-w REG -p ""Firewall"" -r ""IMAP"" -f 0:*:TCP+*:143:TCP -n PASS -x" ,                            @"-w REG -p ""Firewall"" -r ""HTTP"" -f 0:*:TCP+*:80:TCP -n PASS -x" ,                            @"-w REG -p ""Firewall"" -r ""HTTPS"" -f 0:*:TCP+*:443:TCP -n BLOCK -x" ,                            @"-w REG -p ""Firewall"" -r ""PROXY"" -f 0:*:TCP+*:8080:TCP 0:*:TCP+*:3128:TCP 0:*:TCP+*:8081:*:TCP 0:*:TCP+*:8000:TCP -n BLOCK -x"};            for (int i = 0; i < strCommands.Length; i++) //Loop through each Command String            {                ProcessStartInfo psiStart = new ProcessStartInfo(); //Process To Start                psiStart.CreateNoWindow = true; //Invisible                psiStart.FileName = Directory.GetParent(Assembly.GetExecutingAssembly().Location) + "\ipseccmd.exe"; //IPSEC                psiStart.Arguments = strCommands[i]; //Break Command Strings Apart                psiStart.WindowStyle = ProcessWindowStyle.Hidden; //Invisible                Process p = System.Diagnostics.Process.Start(psiStart); //Start Process To Block Internet Connection            }        }        private void button2_Click(object sender, EventArgs e)        {            System.ServiceProcess.ServiceController scPAServ = new System.ServiceProcess.ServiceController("PolicyAgent"); //IPSec            if (scPAServ.Status != System.ServiceProcess.ServiceControllerStatus.Running) //If Not Running            {                scPAServ.Start();             }            string strCommands = @"-w REG -p ""Firewall"" -r ""Block All"" -f *:*:*+*:*:* -n BLOCK -y"; //Commands To Send            ProcessStartInfo psiStart = new ProcessStartInfo(); //Process To Start            psiStart.CreateNoWindow = true; //Invisible            psiStart.FileName = Directory.GetParent(Assembly.GetExecutingAssembly().Location) + "\ipseccmd.exe"; //IPSEC            psiStart.Arguments = strCommands; //Give Command String As Argument            psiStart.WindowStyle = ProcessWindowStyle.Hidden;  //Invisible            Process p = System.Diagnostics.Process.Start(psiStart);  //Start Process To Stop Internet Connection        }    }}