WEBVTT 00:08.810 --> 00:10.400 Whole things come back. 00:10.440 --> 00:14.310 This lesson we're going to talk about the basics of DNS server. 00:14.840 --> 00:21.860 So what does DNS server DNS so Assad use to resolve and domain name includes IP address. 00:22.030 --> 00:22.660 OK. 00:22.860 --> 00:26.060 When you type any domain name into a browser. 00:26.090 --> 00:33.130 So what happens is our browser contacts or local DNS server or find the IP address of the domain. 00:33.280 --> 00:33.600 OK. 00:33.620 --> 00:37.590 And if so we have that IP address in database. 00:37.700 --> 00:42.900 Then it poured that IP address could and that said Get into our browser. 00:43.140 --> 00:43.480 OK. 00:43.520 --> 00:46.710 That Web site gets downloaded in Gohar browser OK. 00:46.880 --> 00:48.910 This is how the procedure works. 00:48.920 --> 00:55.730 So the job of DNS so you screw find the IP address for the corresponding domain. 00:55.970 --> 01:00.920 So here let's understand this and with the help of an image demonstration. 01:01.220 --> 01:06.080 OK before that I want to show you the basic structure of the Internet how it works. 01:06.350 --> 01:06.850 OK. 01:06.950 --> 01:09.570 At the top there on root servers. 01:09.670 --> 01:16.580 OK at the top router was under these root servers there are top level domain names so us all get top 01:16.580 --> 01:20.640 level domain and so this means it contains the database for block. 01:20.660 --> 01:28.250 Com got made and or got us like comments and it is us who called us the source. 01:28.430 --> 01:28.990 OK. 01:29.240 --> 01:36.880 And so was there are second level domain names so as second level domain name so it means like Rupert 01:36.880 --> 01:37.470 Murdoch. 01:37.510 --> 01:42.720 It contains the database for such kind of second level domains. 01:42.860 --> 01:46.140 And on the second Lumines there are some governments. 01:46.410 --> 01:51.880 Ok not every Web site is having subdomain but some of the site content. 01:51.890 --> 01:57.910 So that's why I'm showing here subdomains subelements means like community dot dot com. 01:58.010 --> 01:58.250 OK. 01:58.250 --> 02:05.020 When you go google to document the CT community you will find this common name in your browser and under 02:05.070 --> 02:07.710 some Goman there are Web servers. 02:07.820 --> 02:08.100 OK. 02:08.130 --> 02:08.840 These are. 02:09.000 --> 02:12.820 So we're actually with source on which our Web site is running. 02:12.840 --> 02:21.130 OK you know listen we learn how to install our own web servers and how we open our own Web site with 02:21.130 --> 02:23.300 the help of the web so what IP address. 02:23.330 --> 02:23.820 OK. 02:23.960 --> 02:31.190 So remembering the periscope Web site in the world is impossible for us as a human but remembering them 02:31.540 --> 02:33.220 has a domain name is simple. 02:33.230 --> 02:37.870 So that's why for such reason Goldman is so smart design. 02:37.910 --> 02:38.260 OK. 02:38.330 --> 02:43.220 They are designed to find the IP address for the domains. 02:43.250 --> 02:43.780 OK. 02:44.060 --> 02:48.260 So let's see here how the things work. 02:48.290 --> 02:48.700 OK. 02:48.860 --> 02:54.090 Suppose this client wanted to contact the proveably go over to dot com. 02:54.260 --> 02:54.770 OK. 02:54.890 --> 03:04.140 So what happens is when these Klan types in the browser then that is forwarded to local DNS so. 03:04.280 --> 03:12.830 OK so the local DNS were searches a zone database or cache memory for the IP address of the débutante 03:13.130 --> 03:14.000 dot com. 03:14.140 --> 03:14.580 OK. 03:14.750 --> 03:23.240 If it found the IP address then we'll get that site open in this machine if it contains the IP in its 03:23.330 --> 03:25.980 local database or database. 03:26.000 --> 03:34.300 And if the local DNS server does not Content-Type address then that is forwarded to the speedy and so 03:35.080 --> 03:38.010 or Internet service providers the DNS server. 03:38.170 --> 03:45.170 Ok then the ISP DNS server looks for the IP address of computer but got what got I'm in good luck or 03:45.170 --> 03:54.920 good habits an IP address then forward that our machine and that side get awkward if it does not contain 03:54.980 --> 03:56.850 that IP address then or what. 03:56.870 --> 03:59.930 I use these DNS server for that. 03:59.930 --> 04:07.060 Q. Re do the root servers globally there are 13 root servers are illegal in the world. 04:07.190 --> 04:07.820 OK. 04:07.970 --> 04:11.730 So first all agree is get transferred to one OBD-II. 04:11.950 --> 04:17.010 Or we're kind of good that the roots are worth a look for the world. 04:17.010 --> 04:18.470 We don't want to go cold. 04:18.620 --> 04:19.130 OK. 04:19.220 --> 04:26.500 So root server does not contain the actual IP address for it but it contains a database of dot com. 04:26.510 --> 04:31.300 So in response were Since type resource dot com sources. 04:31.310 --> 04:33.770 That is the top level government in service. 04:34.100 --> 04:39.180 So the ISP is DNS so we're again seen in that jury to. 04:39.470 --> 04:47.200 This was our top level domain name so US and the top level domain name so was looks for the breed of 04:47.220 --> 04:54.110 dog with dot com and they said that we don't have the IP address of that which contains the database 04:54.280 --> 04:55.830 info you to dot com. 04:55.880 --> 05:02.170 So in response we send the IP address of securelevel domain names so us. 05:02.660 --> 05:05.670 And now the ISP is DNS so are contacts. 05:05.690 --> 05:13.280 The second domain names so was the soft of you the blue dot dot com and the Second Level Domain Name 05:13.280 --> 05:21.080 Service says you don't how the IP address offered but which contains the information about subdomains. 05:21.170 --> 05:21.930 OK. 05:22.130 --> 05:28.930 So they sold their info or IP address of this subdomains back to the ISP DNS server. 05:29.330 --> 05:34.630 Ok then the ISP DNS server contacts Deitz subelements. 05:34.780 --> 05:35.300 OK. 05:35.420 --> 05:39.810 And the subdomains contains the actual IP addresses of these verbs so as. 05:39.890 --> 05:45.440 So in response they send the IP address of the Costella domains. 05:45.440 --> 05:53.210 That is not open to come back dice Beazeley and is sold and then Hesperus use that IP address they send 05:53.210 --> 05:59.570 back to our local DNS server and our local DNS so would record that into our local database. 05:59.570 --> 06:06.050 And then this client computer establishes a direct connection with the web server with the help of that 06:06.320 --> 06:07.120 IP address. 06:07.160 --> 06:14.360 OK this is how the prosecutor goes at the background when we type any domain or browser OK this is a 06:14.360 --> 06:17.270 long procedure that goes in the background. 06:17.340 --> 06:24.670 But then in the next time when you're trying to open one to dot com then this procedure is let's skip 06:24.810 --> 06:29.130 that because our local database contains this IP address. 06:29.480 --> 06:32.680 So in this vein this procedure works OK. 06:32.880 --> 06:37.990 Now understanding this I want to show you the typesof DNS servers. 06:38.030 --> 06:38.450 OK. 06:38.690 --> 06:43.660 So then our primary DNS so secondary DNS service. 06:43.670 --> 06:50.870 OK so let's talk about this are you discuss Socola is master DNS server and it reads data from the locals 06:50.870 --> 06:53.660 on file transfer it to the client. 06:53.850 --> 06:58.160 OK so transferring data to the secondary DNS so is OK. 06:58.490 --> 07:00.070 And the next type is secondary. 07:00.080 --> 07:04.110 So it is also called how DNS server. 07:04.240 --> 07:04.600 OK. 07:04.670 --> 07:08.630 And its job is to receive the data from primary DNS service. 07:08.930 --> 07:11.800 It receives the data automatically. 07:11.980 --> 07:12.440 OK. 07:12.620 --> 07:16.190 You can call it as a backup of the primary DNS server. 07:16.220 --> 07:21.270 It contains the data every data that primary server is having. 07:21.470 --> 07:22.070 OK. 07:22.280 --> 07:26.890 So understanding the types I want to show you different records. 07:26.970 --> 07:27.500 OK. 07:27.650 --> 07:32.590 There are different records that does DNS server can hold. 07:32.930 --> 07:35.890 The first one is Eric or it stands for I guess. 07:35.900 --> 07:42.720 This record is used to going to an actual IP address of the server that is IP for IP address. 07:42.850 --> 07:43.320 OK. 07:43.640 --> 07:49.760 The next one needs a a he either got this record is as I recall. 07:49.790 --> 07:58.090 And it does use hold the IP IP address or you can also call it and it maps the hostname puts 128 bit 07:58.090 --> 07:59.240 IP address. 07:59.550 --> 08:02.620 OK the next one is a MX record. 08:02.630 --> 08:07.550 It's called as mailbox a car and it is used to point to your mail server. 08:07.670 --> 08:08.400 OK. 08:08.810 --> 08:15.890 And the next one is Butyric or this record is Coras point correct call it maps and IPV for ideas who 08:15.980 --> 08:17.270 can only call name. 08:17.330 --> 08:22.410 It can be used in reverse look up clinical limits an alternative name. 08:22.510 --> 08:22.890 OK. 08:22.940 --> 08:27.750 For the existing server and the next one is this record. 08:27.770 --> 08:35.460 This record is called as names were record it is used to point to names so was for the domain. 08:35.570 --> 08:37.900 The next one is saw a red card. 08:37.970 --> 08:41.110 It is so called a stock of red card. 08:41.180 --> 08:47.020 It contains some important information about the zone like a serial number. 08:47.030 --> 08:50.850 It's a refresh rate expiry date forward zone. 08:51.200 --> 08:51.670 OK. 08:51.860 --> 08:53.820 We're going to learn everything practically. 08:53.850 --> 08:56.870 How do these recalls what a DNS server. 08:57.050 --> 08:59.280 So for now just understand. 08:59.600 --> 09:02.930 What does it cost and what is the use of it. 09:02.990 --> 09:10.700 The next one is sorry record we stand for services so it can be used to define DCP so on which the government 09:10.730 --> 09:11.680 operates. 09:11.760 --> 09:19.310 And the last one is the exterior is next reg or you can add information about the domain. 09:19.500 --> 09:22.740 OK so this record can be used for that purpose. 09:23.080 --> 09:23.500 OK. 09:23.630 --> 09:29.890 In this way all these records are there all these records that are indeed OK. 09:29.920 --> 09:32.440 Our number is called as Zone. 09:32.610 --> 09:36.750 OK so all each Goman contains different zones. 09:36.860 --> 09:37.190 OK. 09:37.190 --> 09:40.110 You can arrange these recalls in a zone. 09:40.130 --> 09:47.000 So we're going to learn in the next lesson about what this zone is how to create your own DNS so we're 09:47.000 --> 09:49.480 OK we're going to learn everything practically. 09:49.550 --> 09:54.050 But for now just understand these recalls and their use. 09:54.170 --> 10:00.290 So the next lesson we're going to learn practically how Stalin configured you are only in this or.