Blocking Internet Using c#

Question

I am trying to develop a parental software which can be scheduled to block internet in specific intervals. How can I do this in C#?

Can I use System.Net, System.Net.NetworkInformation namespace in c# is there any build in function for blocking/disabling network?

Answer 1

    using System.Diagnostics;
    using System.IO;
    using System.Reflection;

            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
            }
        }

Refer http://forums.codeguru.com/showthread.php?512380-C-.NET-4.0-Blocking-all-internet-traffic-system-wide link for more details.