1 00:00:00,06 --> 00:00:04,01 - [Instructor] Host firewalls are stand-alone firewalls 2 00:00:04,01 --> 00:00:07,01 that only protect a single host. 3 00:00:07,01 --> 00:00:09,06 Firewalls can be categorized 4 00:00:09,06 --> 00:00:13,02 according to the scope of what they protect. 5 00:00:13,02 --> 00:00:15,09 The remaining two types of firewalls. 6 00:00:15,09 --> 00:00:18,06 The first type is host firewalls, 7 00:00:18,06 --> 00:00:22,00 and the other type is network firewalls. 8 00:00:22,00 --> 00:00:26,09 Our focus in this lesson is host firewalls, for now. 9 00:00:26,09 --> 00:00:30,02 Host files monitor activities occurring 10 00:00:30,02 --> 00:00:34,01 on network interfaces on a single host. 11 00:00:34,01 --> 00:00:39,02 They make decisions on whether to accept or reject packets 12 00:00:39,02 --> 00:00:40,09 for a single host. 13 00:00:40,09 --> 00:00:42,09 Major operating systems 14 00:00:42,09 --> 00:00:47,02 come with their own built-in host firewalls. 15 00:00:47,02 --> 00:00:51,03 Let's first take a look at one provided by Windows. 16 00:00:51,03 --> 00:00:56,01 In this case, we'll look at the Windows 10 host firewall. 17 00:00:56,01 --> 00:01:02,01 To get to the Windows 10 host firewall, choose settings. 18 00:01:02,01 --> 00:01:08,00 Click on network and internet. 19 00:01:08,00 --> 00:01:12,00 And then you can see Windows Firewall here. 20 00:01:12,00 --> 00:01:16,07 Click on Windows Firewall, and here it is. 21 00:01:16,07 --> 00:01:19,05 The default configuration of a Windows Firewall 22 00:01:19,05 --> 00:01:23,04 is to drop all the incoming or ingress packets 23 00:01:23,04 --> 00:01:27,05 to accept all the outgoing or egress packets. 24 00:01:27,05 --> 00:01:32,01 And then, packet forwarding is disabled. 25 00:01:32,01 --> 00:01:35,06 To turn Windows Firewall on or off, 26 00:01:35,06 --> 00:01:39,09 you can choose a network, like this. 27 00:01:39,09 --> 00:01:43,03 And use the switch here. 28 00:01:43,03 --> 00:01:48,08 If you want to introduce a new Windows host firewall rule, 29 00:01:48,08 --> 00:01:55,01 click on, allow an app through firewall. 30 00:01:55,01 --> 00:02:00,09 To add a new rule, click on, change settings. 31 00:02:00,09 --> 00:02:05,03 And then, allow another app. 32 00:02:05,03 --> 00:02:14,06 Next, choose the app you want, let's go back. 33 00:02:14,06 --> 00:02:19,05 If you'd like to make some changes in the advanced settings, 34 00:02:19,05 --> 00:02:23,06 click on, advanced settings. 35 00:02:23,06 --> 00:02:27,04 Choose yes. 36 00:02:27,04 --> 00:02:31,06 Now, you have much more flexibility. 37 00:02:31,06 --> 00:02:34,07 On Linux, the built-in firewall module 38 00:02:34,07 --> 00:02:37,02 is called Net Filter. 39 00:02:37,02 --> 00:02:40,00 Let's check out my Ubuntu host. 40 00:02:40,00 --> 00:02:47,00 The default firewall on Ubuntu is Ubuntu Firewall or UFW. 41 00:02:47,00 --> 00:02:55,06 to start the firewall type, sudo ufw enable. 42 00:02:55,06 --> 00:02:58,01 Press enter. 43 00:02:58,01 --> 00:03:00,07 You may need to type the root password 44 00:03:00,07 --> 00:03:05,03 that is given to the administrator password in Windows. 45 00:03:05,03 --> 00:03:07,08 I'm signed on as route, 46 00:03:07,08 --> 00:03:11,09 which is why I don't have to type mine. 47 00:03:11,09 --> 00:03:14,05 If you want to open a new port, 48 00:03:14,05 --> 00:03:22,05 type, sudo ufw allow, and then the port number. 49 00:03:22,05 --> 00:03:27,06 Let's say that the port number is two, two, two, two. 50 00:03:27,06 --> 00:03:30,06 Press enter. 51 00:03:30,06 --> 00:03:33,08 To delete the rule you just added, 52 00:03:33,08 --> 00:03:44,06 type, sudo ufw delete allow two, two, two, two. 53 00:03:44,06 --> 00:03:46,06 Press enter. 54 00:03:46,06 --> 00:03:49,02 Now, you know how to manage your Windows 55 00:03:49,02 --> 00:03:51,08 and Linux host firewalls. 56 00:03:51,08 --> 00:03:55,01 And it's time for you to try this newly obtained knowledge 57 00:03:55,01 --> 00:03:57,00 on your own computer.