1 00:00:08,010 --> 00:00:13,260 This is one of multiple videos discussing network address, translation or net. 2 00:00:13,680 --> 00:00:20,370 In this scenario, we've been told that devices on the inside of our network, such as Router one, 3 00:00:20,370 --> 00:00:28,320 acting as PC one root of four acting as PC two and rather five acting as PC three are not able to ping 4 00:00:28,320 --> 00:00:29,220 Google. 5 00:00:29,340 --> 00:00:31,950 In other words, 828.8.8. 6 00:00:32,430 --> 00:00:35,890 In this topology, router three is configured as Google. 7 00:00:35,910 --> 00:00:37,770 So let's do some verification. 8 00:00:37,950 --> 00:00:40,860 Here's rather one acting as PC one at the top. 9 00:00:42,580 --> 00:00:43,750 Can it ping? 10 00:00:43,870 --> 00:00:45,970 828.8.8. 11 00:00:46,570 --> 00:00:51,220 As we can see in the output, it's not able to ping the Google address. 12 00:00:51,930 --> 00:00:53,460 Show IP route. 13 00:00:53,940 --> 00:01:04,680 We do have a static default route to ten 11254, which is the IP address of router two acting as our 14 00:01:04,680 --> 00:01:05,730 net router. 15 00:01:06,520 --> 00:01:11,770 So let's do a trace to 8.8.8 to date to speed things up. 16 00:01:12,540 --> 00:01:16,080 I'll type no IP domain lookup. 17 00:01:17,400 --> 00:01:18,320 Do that again. 18 00:01:18,330 --> 00:01:21,720 So we hit the default gateway, but we don't go any further. 19 00:01:22,380 --> 00:01:23,250 Just do that again. 20 00:01:23,250 --> 00:01:25,700 So trace to 8.828.8. 21 00:01:26,160 --> 00:01:31,650 It gets to the default gateway, which is rather two but doesn't get any further. 22 00:01:32,070 --> 00:01:37,140 So can rather to ping google paying 8.828.8. 23 00:01:37,650 --> 00:01:38,550 Yes, it can. 24 00:01:38,550 --> 00:01:42,270 It can ping the google IP address of quadruple eight. 25 00:01:42,630 --> 00:01:43,770 This is our net router. 26 00:01:43,770 --> 00:01:46,800 So let's do some net debug. 27 00:01:46,820 --> 00:01:48,420 So debug ip net. 28 00:01:48,480 --> 00:01:49,530 Press enter. 29 00:01:50,510 --> 00:01:52,640 Net debugging is now enabled. 30 00:01:53,370 --> 00:01:56,340 Ping from rota one to google. 31 00:01:56,790 --> 00:02:03,270 We not getting any output in the net debug show ip net translations. 32 00:02:03,750 --> 00:02:05,700 There are no net translations. 33 00:02:05,700 --> 00:02:08,610 Show IP net statistics. 34 00:02:09,180 --> 00:02:09,570 Okay. 35 00:02:09,570 --> 00:02:12,000 So can you find the problem? 36 00:02:12,210 --> 00:02:15,540 Can you see where the issue is in this output? 37 00:02:17,470 --> 00:02:18,300 Notice here. 38 00:02:18,310 --> 00:02:20,800 Total active translations is zero. 39 00:02:21,280 --> 00:02:24,520 We had peak translations previously of two. 40 00:02:24,850 --> 00:02:26,280 And here's the problem. 41 00:02:26,290 --> 00:02:28,830 There are no outside interfaces. 42 00:02:28,840 --> 00:02:32,230 There are only inside interfaces. 43 00:02:32,470 --> 00:02:37,630 Gigabyte 000102 and zero three are configured as inside interfaces. 44 00:02:38,290 --> 00:02:40,300 Looking at rather two's interfaces. 45 00:02:40,300 --> 00:02:41,410 That's incorrect. 46 00:02:41,650 --> 00:02:45,420 This interface gigabyte is zero one is on the outside. 47 00:02:45,430 --> 00:02:47,500 In other words, it's connected to the internet. 48 00:02:47,980 --> 00:02:50,710 These three interfaces are on the inside. 49 00:02:51,010 --> 00:02:54,760 In other words, they are on the local LAN and they should be netted. 50 00:02:55,440 --> 00:02:59,040 So before I do a change, let's look at the config. 51 00:02:59,310 --> 00:03:04,260 This interface is inside according to the configuration. 52 00:03:04,560 --> 00:03:11,130 This interface is the inside according to the config, but according to the topology that should be 53 00:03:11,130 --> 00:03:12,090 the outside. 54 00:03:12,480 --> 00:03:14,250 So that's wrong. 55 00:03:14,460 --> 00:03:22,320 Other interfaces are configured correctly as the inside interface, but we need to change gigabit zero 56 00:03:22,320 --> 00:03:25,920 one and make that the outside interface. 57 00:03:25,950 --> 00:03:26,970 Notice the problem. 58 00:03:26,970 --> 00:03:30,060 When I hit Enter we told that it's inside. 59 00:03:30,060 --> 00:03:32,790 So no IP net inside. 60 00:03:33,700 --> 00:03:35,740 IP net outside. 61 00:03:35,950 --> 00:03:38,140 So we've made it the outside interface now. 62 00:03:38,170 --> 00:03:39,520 Show IP. 63 00:03:39,550 --> 00:03:44,440 Net statistics shows us that gigabit is there. 64 00:03:44,440 --> 00:03:46,480 One is the outside. 65 00:03:46,840 --> 00:03:50,110 These three interfaces are inside interfaces. 66 00:03:50,530 --> 00:03:52,510 So in of one, can we ping Google? 67 00:03:52,540 --> 00:03:53,740 Yes, we can. 68 00:03:54,280 --> 00:03:56,860 We can see the net translations on rather too. 69 00:03:56,890 --> 00:04:05,680 So source IP address of ten 111 was translated to 828.8254 destination being Google. 70 00:04:05,680 --> 00:04:12,340 We got the reply back and the reply was translated, so that looks good. 71 00:04:12,580 --> 00:04:17,829 What about rate of four and root of five acting as internal hosts? 72 00:04:17,980 --> 00:04:21,459 Ping 8.8.8.8. 73 00:04:21,490 --> 00:04:24,160 Ping succeeds of five. 74 00:04:24,160 --> 00:04:27,550 Ping 8.8.8.8 Ping succeeds. 75 00:04:28,090 --> 00:04:33,550 So we've resolved the network address translation issue in this topology. 76 00:04:33,730 --> 00:04:40,750 Don't forget, you need to configure inside and outside interfaces correctly when configuring network 77 00:04:40,750 --> 00:04:41,950 address translation. 78 00:04:42,910 --> 00:04:44,950 I hope you found this video useful. 79 00:04:45,460 --> 00:04:50,620 If it's been of benefit to you, please like it and please subscribe to my YouTube channel. 80 00:04:50,950 --> 00:04:52,990 I wish you all the very best.