Block all connections in Windows firewall, except some IP addresses during work hours. For Windows Vista, 7, 8 and 10.

C# Windows Firewall

private static INetFwPolicy2 getCurrPolicy()
        {
            INetFwPolicy2 fwPolicy2;
            Type tNetFwPolicy2 = Type.GetTypeFromProgID("HNetCfg.FwPolicy2");
            fwPolicy2 = (INetFwPolicy2)Activator.CreateInstance(tNetFwPolicy2);
            return fwPolicy2;
        }

        INetFwPolicy2 fwPolicy2 = getCurrPolicy();

        private async void Form1_LoadAsync(object sender, EventArgs e)
        {
            bool addRule = true;

            if (fwPolicy2.get_FirewallEnabled(NET_FW_PROFILE_TYPE2_.NET_FW_PROFILE2_DOMAIN) == false) //turn on firewall, if it's off
                fwPolicy2.FirewallEnabled[NET_FW_PROFILE_TYPE2_.NET_FW_PROFILE2_DOMAIN] = true;

            foreach (INetFwRule rule in fwPolicy2.Rules)
            {
                if (rule.Name == "Allow all local intranet")
                    addRule = false;
            }

            if (addRule)
            {
                //let local IPs through (intranet, jobboss, etc)
                INetFwRule firewallRule = (INetFwRule)Activator.CreateInstance(Type.GetTypeFromProgID("HNetCfg.FWRule"));
                firewallRule.Action = NET_FW_ACTION_.NET_FW_ACTION_ALLOW;
                firewallRule.Direction = NET_FW_RULE_DIRECTION_.NET_FW_RULE_DIR_OUT;
                firewallRule.Enabled = true;
                firewallRule.InterfaceTypes = "All";
                firewallRule.LocalAddresses = "10.1.10.1-10.1.10.255"; //local IP's assumed to be in 10.1.10. range
                firewallRule.RemoteAddresses = "10.1.10.1-10.1.10.255";
                firewallRule.Name = "Allow all local intranet";
                fwPolicy2.Rules.Add(firewallRule);
            }

            TimeSpan span = new TimeSpan(0, 0, 0, 1, 0); //once per second
            await checkTime(span);
        }

        public async Task checkTime(TimeSpan interval)
        {
            while (true)
            {
                //written in military time
                //work is from 6-9, 9:20-12:00, 12:30-5:00
                //9:00-9:20 break, 12:00-12:30 break, 5:00 left work
                if (Convert.ToInt32(DateTime.Now.ToString("HHmmss")) > 000000 && Convert.ToInt32(DateTime.Now.ToString("HHmmss")) < 060000 ||
                    Convert.ToInt32(DateTime.Now.ToString("HHmmss")) > 090000 && Convert.ToInt32(DateTime.Now.ToString("HHmmss")) < 091959 ||
                    Convert.ToInt32(DateTime.Now.ToString("HHmmss")) > 120000 && Convert.ToInt32(DateTime.Now.ToString("HHmmss")) < 122959 ||
                    Convert.ToInt32(DateTime.Now.ToString("HHmmss")) > 170000 && Convert.ToInt32(DateTime.Now.ToString("HHmmss")) < 240000)
                    fwPolicy2.DefaultOutboundAction[NET_FW_PROFILE_TYPE2_.NET_FW_PROFILE2_DOMAIN] = NET_FW_ACTION_.NET_FW_ACTION_ALLOW;
                else
                    fwPolicy2.DefaultOutboundAction[NET_FW_PROFILE_TYPE2_.NET_FW_PROFILE2_DOMAIN] = NET_FW_ACTION_.NET_FW_ACTION_BLOCK; //block all outbound default

                await Task.Delay(interval);
            }
        }

None is blocked but allowed