1 00:00:05,550 --> 00:00:09,040 Okay so I'm going to set this to real time to end this simulation. 2 00:00:09,580 --> 00:00:11,170 Let's run another simulation. 3 00:00:11,830 --> 00:00:18,470 And what I'm going to do on the P.C. is open up a different application. 4 00:00:18,470 --> 00:00:23,200 You can see the web server has displayed the website on that server. 5 00:00:23,200 --> 00:00:24,950 I'll close this down now. 6 00:00:25,030 --> 00:00:29,740 So that was just a built in web server running on that internal server. 7 00:00:29,890 --> 00:00:32,680 What I'll do here is let's start. 8 00:00:32,740 --> 00:00:36,610 Email Let's compose an e-mail. 9 00:00:36,780 --> 00:00:43,900 In this example the only email address used is Peter at Cisco dot com going to our server again you 10 00:00:43,900 --> 00:00:47,050 can see that we're running multiple services on the server. 11 00:00:47,080 --> 00:00:51,770 We've got HDP TFT IP FCP package. 12 00:00:51,790 --> 00:00:53,610 We've got an e-mail server. 13 00:00:53,920 --> 00:00:58,150 The only user account I've configured on the server is Peter. 14 00:00:58,150 --> 00:01:00,860 You could create a different one if you wanted to. 15 00:01:00,910 --> 00:01:03,510 So you could add another user for yourself. 16 00:01:03,550 --> 00:01:10,440 We've got two e-mail services running here simple mail transfer protocol is empty P and pop three pop 17 00:01:10,440 --> 00:01:15,900 three is an older protocol that allows us to retrieve e-mail from an email server is empty. 18 00:01:15,910 --> 00:01:21,220 He allows us to transmit e-mail these protocols use different port numbers. 19 00:01:21,550 --> 00:01:25,240 So let's actually show that practically. 20 00:01:25,240 --> 00:01:29,440 So test e-mail test e-mail 21 00:01:31,900 --> 00:01:36,880 showing port numbers before I click send. 22 00:01:37,110 --> 00:01:45,340 I want to make sure that I'm running simulation mode which I am and now I'll click send S.M. T.P. users 23 00:01:45,910 --> 00:01:53,740 TTP looking at that TTP message inbound Peter you we have our source and destination MAC addresses. 24 00:01:53,820 --> 00:01:58,130 P.S. talking to the server PCI IP address talking to the server ip address. 25 00:01:58,350 --> 00:02:02,410 So layer to layer 3 this is IP version 4. 26 00:02:02,430 --> 00:02:08,640 Again just to recap make sure that you know this stuff at least to the type field indicates that the 27 00:02:08,640 --> 00:02:15,220 protocol at least three is IP version for IP version 6 has a different protocol number. 28 00:02:15,390 --> 00:02:21,260 We know the protocol at layer four because of this number DCP. 29 00:02:21,270 --> 00:02:30,900 So that indicates TTP at leave for destination port number is 25 what is 25 looking at the eye on a 30 00:02:30,900 --> 00:02:36,010 Web site port 25 is simple mail transfer it's empty. 31 00:02:36,660 --> 00:02:42,710 So random port number we femoral port number going to port 25. 32 00:02:42,810 --> 00:02:49,680 So we are sending an email to the server using S.M. T.P. so push that along. 33 00:02:49,680 --> 00:02:58,430 So we've got our TTP what's called the three way handshake that takes place so we have to use what are 34 00:02:58,430 --> 00:03:01,460 called synchronization bits and it has to be an acknowledgement. 35 00:03:01,520 --> 00:03:08,510 I'll talk about that in a separate video but notice here we've got our inbound PDA going to the server 36 00:03:08,840 --> 00:03:14,080 once again source port number destination port number at layer four. 37 00:03:14,090 --> 00:03:16,150 You can see S.M. teepee data. 38 00:03:16,580 --> 00:03:24,500 So we are sending data to the server this will be our actual email going to the server. 39 00:03:24,720 --> 00:03:29,140 And now the server replies back looking at that. 40 00:03:29,280 --> 00:03:39,120 The message to the P.S. notice port 25 talking to the agreed port number of 1027 SMP B data. 41 00:03:39,120 --> 00:03:43,440 Another reason we have the TCB handshake is we have to agree what port numbers we're going to be talking 42 00:03:43,440 --> 00:03:43,920 on. 43 00:03:44,070 --> 00:03:48,080 If you choose a random port number to talk to me how will I know what your random port number is. 44 00:03:48,180 --> 00:03:53,940 You need to tell me that or your ephemeral port number you need to tell me what that is. 45 00:03:53,940 --> 00:04:00,530 Notice also we have sequence numbers and acknowledgements in the messages so that takes place. 46 00:04:00,530 --> 00:04:07,130 And now suddenly we've got some more TTP let's have a look at that TTP message inbound PD you still 47 00:04:07,130 --> 00:04:12,990 using port 25 so a bunch of TTP messages 48 00:04:16,600 --> 00:04:18,290 a run out of space there 49 00:04:24,150 --> 00:04:27,870 for my packet tracer has locked up so I'm going to restart it. 50 00:04:27,920 --> 00:04:41,820 This may happen sometimes with packet tracer. 51 00:04:41,840 --> 00:04:44,280 Now you may encounter problems like this and Packet Tracer. 52 00:04:44,340 --> 00:04:50,430 Just bear with the application it's not perfect but it's well worth the trouble because you'll learn 53 00:04:50,430 --> 00:04:53,590 a lot to using this application case. 54 00:04:53,600 --> 00:04:54,420 I didn't get my email. 55 00:04:54,420 --> 00:05:03,610 Let's try that again someone to send it to Peter at Cisco dot com test to test to send my email now 56 00:05:03,610 --> 00:05:05,140 to retrieve my email. 57 00:05:05,140 --> 00:05:12,220 I'm going to go to simulation mode and I'm going to click retrieve to get my email from the server. 58 00:05:12,220 --> 00:05:13,450 So what have we got. 59 00:05:13,450 --> 00:05:17,730 Share what message is this notice. 60 00:05:17,730 --> 00:05:26,910 This is T C P but the port number is 1 1 0 what is 1 1 0 on the eye on a website. 61 00:05:26,910 --> 00:05:31,570 We can see that this is post office Protocol Version 3 or pop 3. 62 00:05:31,680 --> 00:05:43,490 So this is the protocol used to retrieve the message from the server. 63 00:05:43,540 --> 00:05:46,200 So here's the actual POP 3 message. 64 00:05:46,270 --> 00:05:50,720 Let's have a look at that inbound means it's inbound to the switch. 65 00:05:50,750 --> 00:05:53,840 So it will be the same inbound and outbound on the switch. 66 00:05:53,870 --> 00:06:00,320 Source MAC address is P.C. destination MAC addresses server type is 800 telling us that it's IP version 67 00:06:00,320 --> 00:06:07,070 4 source and destination ip addresses PCI and server protocol use it Layer 4 is TTP we can see that 68 00:06:07,070 --> 00:06:07,580 here. 69 00:06:07,850 --> 00:06:12,110 Source port number used by the PCI is this destination port number is 110. 70 00:06:12,260 --> 00:06:20,600 This is pop 3 data so that will go to the server message goes back to the P.C. we've got some TTP messages 71 00:06:22,240 --> 00:06:28,820 I'll clear my event list it's got a real time and then hopefully on my P.C. what you can see is I've 72 00:06:28,820 --> 00:06:32,510 received my messages Now see here's my original message. 73 00:06:32,510 --> 00:06:37,910 Actually that's been retrieved from the server and here's has my test to message that was received from 74 00:06:37,910 --> 00:06:39,280 the server. 75 00:06:39,310 --> 00:06:44,990 Now I can spend a long time showing you different protocols here as an example you could open up a command 76 00:06:45,020 --> 00:06:52,760 prompt and then open up FCP to the server and log in as Cisco Cisco username Cisco password Cisco and 77 00:06:52,770 --> 00:07:00,410 use the command D.R. to see the files on the server if you ran simulation mode you'd be able to see 78 00:07:00,530 --> 00:07:03,890 those messages to the server. 79 00:07:03,890 --> 00:07:12,380 So spend some time having a look at the different protocols use email use HDP use FCP to see the messages 80 00:07:12,560 --> 00:07:15,800 and the protocols simulation mode in packet traces. 81 00:07:15,800 --> 00:07:17,670 Great to actually see what's going on. 82 00:07:17,840 --> 00:07:21,130 So fantastic way to actually learn the protocols.