1 00:00:00,470 --> 00:00:03,950 DNS or domain name system service. 2 00:00:07,590 --> 00:00:13,020 So in our previous lessons, of course, we mentioned the IP, which is the Internet protocol, so a 3 00:00:13,020 --> 00:00:17,340 computer must have an IP to communicate over network. 4 00:00:18,480 --> 00:00:22,830 So if he cannot receive an IP, it cannot exchange data over the network. 5 00:00:24,190 --> 00:00:31,960 OK, so you know that in order to communicate with one computer, another computer will need to know 6 00:00:31,960 --> 00:00:35,230 the IP address of the computers that it wants to communicate with. 7 00:00:36,710 --> 00:00:44,690 It's going to be difficult for all computers that will be contacted to remember a numerical IP address 8 00:00:44,690 --> 00:00:45,110 value. 9 00:00:45,970 --> 00:00:49,990 Therefore, the DNS or domain name system protocol has emerged. 10 00:00:51,510 --> 00:00:58,320 The DNS protocol matches computer threads to their names, so it makes name IP matching possible. 11 00:00:59,310 --> 00:01:02,730 This way we can only access a site that we know the name of. 12 00:01:04,080 --> 00:01:10,040 Now, there are servers that provide a DNS service, and these are called DNS servers. 13 00:01:11,320 --> 00:01:16,360 So the DNS protocol uses the UDP, TCP, Port 53. 14 00:01:18,290 --> 00:01:23,030 And a computer automatically receives a DNS server address when it receives an IP. 15 00:01:24,780 --> 00:01:27,450 However, we can also manually define this address. 16 00:01:29,390 --> 00:01:36,020 So if we want to communicate with a computer without a defined DNS over the network, we're going to 17 00:01:36,020 --> 00:01:40,040 need to know the IP address of each computer or web address if we want to reach. 18 00:01:40,700 --> 00:01:43,100 Otherwise, communications are going to take place. 19 00:01:45,420 --> 00:01:49,530 So the DNS protocol works on our computer as follows. 20 00:01:51,800 --> 00:01:57,410 Let's suppose that we want to access dub, dub, dub dub, Google Dotcom would ever want to do that. 21 00:01:58,290 --> 00:02:06,660 Anyway, when we type it into our Web browser and click on Enter the Web browser for was a request to 22 00:02:06,660 --> 00:02:12,810 the network card, the network card then receives a request and forwards a request to the DNS server 23 00:02:13,170 --> 00:02:15,150 defined in the IP settings. 24 00:02:15,450 --> 00:02:23,070 And the DNS server transmits the IP information from Google dot com to the requesting computer, and 25 00:02:23,070 --> 00:02:28,140 the computer receives a request to the network layer and transmits it to the web browser. 26 00:02:29,470 --> 00:02:31,870 And the Web browser shows us our request. 27 00:02:32,980 --> 00:02:37,780 So different commands are used on Linux and Windows computers to view DNS settings. 28 00:02:39,810 --> 00:02:41,790 If you were on Windows Computer. 29 00:02:43,260 --> 00:02:46,790 Run, run is written in command. 30 00:02:48,600 --> 00:02:52,590 Can config all is entered on the incoming screen? 31 00:02:53,910 --> 00:02:57,180 And then the address that you see here is a DNS server address. 32 00:02:59,150 --> 00:02:59,960 Lennix. 33 00:03:03,980 --> 00:03:04,780 Is a bit different. 34 00:03:06,320 --> 00:03:15,560 Open up terminal type leaf pad, slash slash resolve dot conf at the end of the command prompt, enter 35 00:03:16,220 --> 00:03:19,640 the DNS server address of the Linux computer's displayed on the screen. 36 00:03:21,910 --> 00:03:23,380 And map and scanning. 37 00:03:24,810 --> 00:03:31,050 So when we scan, then map, it attempts to resolve the DNS name of each IP address, it scans by default. 38 00:03:32,490 --> 00:03:38,980 So for this purpose, it performs an IP name analysis on the DNS server for each IP address. 39 00:03:39,420 --> 00:03:44,640 So in this case, depending on the DNS server name, IP analysis may take a little time. 40 00:03:45,680 --> 00:03:54,020 And this increases the scanning time, of course, so to prevent this, when we scan with an Perret 41 00:03:54,830 --> 00:04:00,260 MRI scans without DNS resolution and map our scanning. 42 00:04:01,600 --> 00:04:06,340 So when we scan within map, the names of the target servers can always give us some clues. 43 00:04:07,430 --> 00:04:13,730 So that means in this case, the IP name analysis is required for this will use the R parameter. 44 00:04:14,740 --> 00:04:19,030 And then this parameter requires DNS resolution for each IP address.