1 00:00:07,990 --> 00:00:16,550 This is one of multiple videos discussing network address translation or not in a previous video I showed 2 00:00:16,550 --> 00:00:25,820 you how to configure static Nat translations to allow outside hosts hosts on the Internet access to 3 00:00:25,820 --> 00:00:35,060 multiple internal servers running in your local network router to in this example is nothing the three 4 00:00:35,060 --> 00:00:46,010 servers on the left to public IP addresses in the 8 8 8 range making them available to the PC. 5 00:00:46,010 --> 00:00:55,120 Now the issue here is that you are using an external or public IP address per internal server. 6 00:00:56,810 --> 00:01:03,230 Is it possible to use a single IP address such as an IP address at your home. 7 00:01:05,580 --> 00:01:14,890 To expose multiple servers or devices to the Internet. 8 00:01:14,910 --> 00:01:23,420 So in other words can you set up servers in your home network or small medium business network and allow 9 00:01:23,780 --> 00:01:28,260 people to access those servers using the same IP address. 10 00:01:29,330 --> 00:01:30,950 And the answer is yes. 11 00:01:30,980 --> 00:01:40,660 So at the moment I've got four net commands configured what I've done is configure gigabit 0 1 as the 12 00:01:40,660 --> 00:01:48,040 outside interface on this router and the other interfaces gigabit 00 two and three are configured as 13 00:01:48,550 --> 00:01:50,530 inside Nat interfaces. 14 00:01:51,300 --> 00:01:58,100 See my previous video for the configuration of static not using multiple IP addresses once again. 15 00:01:58,350 --> 00:02:07,020 But here what we're going to do is use the command IP not inside source because we want to Nat these 16 00:02:07,140 --> 00:02:11,100 servers to an individual IP address. 17 00:02:11,100 --> 00:02:18,860 So when we use the common IP Nat inside source static The inside a local IP address of the server. 18 00:02:18,870 --> 00:02:23,060 In other words it's real IP addresses tend wondered wondered one. 19 00:02:23,460 --> 00:02:29,230 And we get to a virtual IP address of 8 8 8 8 to 1. 20 00:02:29,480 --> 00:02:36,180 If we did that we would be using that entire IP address for that individual server. 21 00:02:36,180 --> 00:02:42,480 So what we're going to do here rather is specify TCAP or UDP. 22 00:02:42,480 --> 00:02:49,170 So TZP And now we are going to specify the inside IP address and the port number on that server is going 23 00:02:49,170 --> 00:02:54,700 to be 23 and the virtual IP address of the server is going to be this. 24 00:02:54,980 --> 00:02:59,720 And in this example I'll use port 23 extendable. 25 00:03:00,110 --> 00:03:07,850 So basically what I'm saying is that when this device sends traffic to port 23 and destination IP address 26 00:03:07,870 --> 00:03:13,690 8 8 8 8 1 the router is going to Nottage and send the traffic to that server. 27 00:03:14,150 --> 00:03:19,420 So let's test at rather three in this example is acting as our PC. 28 00:03:19,910 --> 00:03:23,800 So all telnet to 8 8 8 to 1. 29 00:03:23,910 --> 00:03:33,890 Notice I can log in to server 1 over there and to prove it we can type show IP interface brief to see 30 00:03:34,250 --> 00:03:36,200 the IP address of the server 31 00:03:39,010 --> 00:03:45,950 OK but now how do you do this for the other service. 32 00:03:45,950 --> 00:03:54,920 So in this example I'm going to use a random port number that we femoral port number of 65000 23 and 33 00:03:54,920 --> 00:03:59,810 change that to tendered one to two to two. 34 00:03:59,810 --> 00:04:06,110 So in other words when traffic gets sent by the PC to the router with the destination IP address of 35 00:04:06,830 --> 00:04:16,340 8 8 8 8 or 1 destination port number of 65000 and 23 the road is going to not get to us internal IP 36 00:04:16,340 --> 00:04:17,270 address. 37 00:04:18,090 --> 00:04:30,550 And change the port number to 23 so on Rodda 3 when we use the telnet IP address question mark C'mon 38 00:04:31,060 --> 00:04:33,660 we can now specify a port number. 39 00:04:33,970 --> 00:04:42,420 So sixty five thousand twenty three connection is opened and we are now on route a full 40 00:04:45,280 --> 00:04:49,090 show IP interface brief. 41 00:04:49,480 --> 00:05:04,600 We are on route a full but using the same IP address 8 8 8 or 1 but a different port in them which means 42 00:05:04,600 --> 00:05:07,000 the traffic goes to a different server. 43 00:05:07,000 --> 00:05:08,340 Let's create another one. 44 00:05:08,410 --> 00:05:11,400 So IP not inside source. 45 00:05:11,440 --> 00:05:13,150 Static TZP 46 00:05:16,620 --> 00:05:20,740 Let's send it to route of five acting service free. 47 00:05:20,830 --> 00:05:33,220 But in this case I'll use a port number of 65000 and 24 hour show run pipe include Nat shows us the 48 00:05:33,670 --> 00:05:44,410 static Nat commands that over here in Colorado for some back on Route 3 which is acting as our PC show 49 00:05:44,410 --> 00:05:50,360 at the interface brief notice this is the IP address of the PC it's on the Internet. 50 00:05:50,520 --> 00:05:56,660 And what I'll do now is telnet to port sixty Falzon and 24 51 00:05:59,860 --> 00:06:05,670 now I'm on route 5 with IP address 10 at one of 3.3. 52 00:06:05,830 --> 00:06:12,950 What I'll do now is use the command control shift 6 x to jump back to Route 3 and go to port number 53 00:06:13,430 --> 00:06:22,400 65000 23 on write a full control shift 6 x to jump back shows sessions. 54 00:06:22,420 --> 00:06:30,210 Shows me that I've got two sessions open what I'll do now is telnet to port 23. 55 00:06:30,340 --> 00:06:40,340 Now I'm on route 1 controllers shift 6 x shows that I've got three sessions open show IP not on router 56 00:06:40,380 --> 00:06:43,650 2 shows me those connections. 57 00:06:43,650 --> 00:06:53,490 So this PC 8 8 today or four which is this PC here has initiated sessions 2 8 8 8 8 1 pt. 23 which is 58 00:06:53,490 --> 00:07:00,280 going to that host one of the old TZP sessions is still held in the NAT translation table. 59 00:07:00,280 --> 00:07:07,710 Hence we are seeing two of them but we've also got the same PC sending traffic to eight today today 60 00:07:07,730 --> 00:07:14,860 day one but Port sixty five thousand twenty three that's going to a different host on port 23 and we've 61 00:07:14,860 --> 00:07:16,750 also got this entry. 62 00:07:16,750 --> 00:07:25,960 So that's an example of how to use the same global IP address or Internet IP address for multiple internal 63 00:07:25,960 --> 00:07:28,180 hosts or devices. 64 00:07:28,180 --> 00:07:34,390 So once again if you're at home and you wanted to make your devices available on the internet but you 65 00:07:34,390 --> 00:07:38,230 only had one public ip address this is how you do it. 66 00:07:38,320 --> 00:07:45,940 The only thing to remember is that you can't use the same port number for multiple internal devices 67 00:07:46,450 --> 00:07:50,780 because otherwise the router can't differentiate between the that translations. 68 00:07:50,830 --> 00:07:56,770 So hence we use different port numbers for the different hosts. 69 00:07:56,770 --> 00:08:02,450 Even though it's the same external IP address I hope you found this useful. 70 00:08:02,590 --> 00:08:08,650 This is out of the scope of a CCMA exam but hopefully give you some real world knowledge that you can 71 00:08:08,650 --> 00:08:09,380 apply. 72 00:08:09,760 --> 00:08:12,350 If you enjoyed this video please like it. 73 00:08:12,500 --> 00:08:14,160 I wish you all the very best.