1 00:00:08,470 --> 00:00:14,260 This is one of multiple network address translation or not videos. 2 00:00:14,320 --> 00:00:16,300 This is a troubleshooting video. 3 00:00:16,300 --> 00:00:23,950 In this scenario you've been told that some hosts in the internal network are not able to connect to 4 00:00:23,950 --> 00:00:24,840 the Internet. 5 00:00:25,880 --> 00:00:33,500 In this genus three typology I've got four rods broader two and three are acting as PCs they have IP 6 00:00:33,500 --> 00:00:35,300 routing disabled. 7 00:00:35,510 --> 00:00:41,990 They have the default gateways configured as Router one router one is going to act as our network address 8 00:00:41,990 --> 00:00:46,400 translation Rodda and Foy's going to act as Google. 9 00:00:46,430 --> 00:00:56,570 So let's test the network can write a one paying the DNS server Subroto for pretending to be the Google 10 00:00:56,570 --> 00:00:57,670 DNS server. 11 00:00:57,950 --> 00:01:00,540 Yes it can. 12 00:01:00,550 --> 00:01:04,430 What about router 3. 13 00:01:04,550 --> 00:01:07,880 Doesn't look like it's able to ping. 14 00:01:08,150 --> 00:01:08,960 Let's investigate. 15 00:01:08,960 --> 00:01:16,310 So show IP wrought we can see that IP routing is disabled on those router but its default gateways configured 16 00:01:16,310 --> 00:01:18,920 is 10 more than one. 17 00:01:18,930 --> 00:01:25,920 What about on Route 2 rather 2 has the same configuration wrote it too. 18 00:01:26,670 --> 00:01:37,580 Can ping 10 1 1 1 and can ping Google router 3 can paying 10 1 1 1. 19 00:01:38,090 --> 00:01:48,390 We could trace to Google it gets to its default gateway 10 1 1 1 but then nothing happens. 20 00:01:52,020 --> 00:02:01,870 So we have a timeout on brought a 1 so brought a one let's confirm the IP address I think firstly if 21 00:02:01,910 --> 00:02:10,290 0 slash one has an IP address of 10 1 1 1 that's the inside of the network. 22 00:02:10,460 --> 00:02:15,260 If 0 0 has an IP address of 8 8 8 2 5 4. 23 00:02:15,680 --> 00:02:27,760 So let's do it debug on this router debug IP Nat a was able to pinged Google before and still can and 24 00:02:27,770 --> 00:02:33,450 we can see the NAT translation taking place when Rotto three pings. 25 00:02:33,450 --> 00:02:38,170 Google dot com we don't see any net translations. 26 00:02:38,180 --> 00:02:38,970 Sure. 27 00:02:39,170 --> 00:02:44,160 IP net translations. 28 00:02:44,400 --> 00:02:48,890 So we see a net translation for Rodda too. 29 00:02:48,980 --> 00:02:50,660 That's the IP address of rodded. 30 00:02:50,670 --> 00:03:00,680 So show IP face brief will show us that so we can see the translation for rodded too. 31 00:03:00,960 --> 00:03:04,880 But we don't see a net translation for Rodda 3. 32 00:03:05,010 --> 00:03:08,100 What happens if we clear the natural translations. 33 00:03:11,020 --> 00:03:13,980 So there are no net translations at the moment. 34 00:03:14,170 --> 00:03:23,370 When I ping from router three to Google we suddenly see translations and the pings start succeeding 35 00:03:24,710 --> 00:03:26,430 Ken brought it to Payne. 36 00:03:26,430 --> 00:03:27,310 Google dot com 37 00:03:30,440 --> 00:03:37,710 noticed router too can now no longer ping Google that come let's clear the net translations again. 38 00:03:40,630 --> 00:03:42,920 Ratatouille is now able to pin Google dot com 39 00:03:46,320 --> 00:03:47,890 but Raanta 3 is not 40 00:03:51,210 --> 00:04:00,810 so it looks like when we clear the translations one device is able to connect to Google Sherburne 41 00:04:06,170 --> 00:04:14,930 if 0 0 is correctly configured with an IP address and is configured as the outside interface. 42 00:04:15,050 --> 00:04:22,400 If a zero slushed one has the correct insight IP address and is configured as the inside Knecht interface 43 00:04:24,660 --> 00:04:25,340 OK. 44 00:04:25,570 --> 00:04:27,980 Can you see the problem. 45 00:04:28,120 --> 00:04:29,460 What's going on here. 46 00:04:30,710 --> 00:04:33,000 I noticed when I clicked the next translation again 47 00:04:35,950 --> 00:04:42,090 and then ping from Rodda three which wasn't able to ping previously the pings. 48 00:04:42,080 --> 00:04:43,560 Now succeed. 49 00:04:43,820 --> 00:04:46,260 Show IP match translation. 50 00:04:46,810 --> 00:04:54,520 We now see a net translation 4 out of three so going back through the configuration and I'll scroll 51 00:04:54,520 --> 00:04:58,040 down to the net config. 52 00:04:58,230 --> 00:05:01,470 Can you see the problem OK. 53 00:05:01,540 --> 00:05:04,870 Have a look at this IP not inside source. 54 00:05:04,900 --> 00:05:13,270 The last one which is pointing to access list one that means that any IP address will be netted but 55 00:05:13,270 --> 00:05:23,860 it's pointing to a poll called my poll the Nat Poole is configured with a starting IP address of 8 8 56 00:05:24,060 --> 00:05:30,840 8 to 2 and an ending IP address of 8 8 8 to 2. 57 00:05:30,860 --> 00:05:39,740 That means we've only put one IP address in the poll hence only one internal host can be netted at any 58 00:05:39,740 --> 00:05:42,420 given time. 59 00:05:42,460 --> 00:05:52,840 So let's remove this. 60 00:05:52,910 --> 00:05:56,560 We are told that we can't remove it so let's clear the ARPANET translations. 61 00:05:58,250 --> 00:06:03,100 Translations staw and trying to remove it again. 62 00:06:03,350 --> 00:06:07,090 So remove now. 63 00:06:07,310 --> 00:06:14,730 What we should do is add additional IP addresses to the poll so and from 2 to 20. 64 00:06:15,050 --> 00:06:23,850 Previously it was from 8 8 8 0 2 2 8 8 8 to 2 but now it's going from 2 to 20. 65 00:06:23,930 --> 00:06:37,240 So show run piping clewed that will show us that configuration so Ken rotas three paying Google yes 66 00:06:37,240 --> 00:06:38,250 it can. 67 00:06:38,260 --> 00:06:48,740 Ken Rodda to ping Google yes it can it took it a while to ping Google router 3 can ping Google and we 68 00:06:48,740 --> 00:06:52,270 see the net translations for both of them. 69 00:06:52,730 --> 00:06:59,760 Notice please that the one device is not to 2 8 8 8 or 3. 70 00:07:00,090 --> 00:07:07,410 And the other one is netted to 8 today to today Touche so show IP net translation shows us that two 71 00:07:07,410 --> 00:07:13,400 addresses in the pool have been used to show IP not statistics. 72 00:07:15,030 --> 00:07:23,950 At the moment we have a six dynamic translations notice of polls shows us the list of IP addresses. 73 00:07:24,160 --> 00:07:31,070 So we have a starting address of 8 8 today 8 2 and ending of 8 8 8 to 20. 74 00:07:31,090 --> 00:07:35,950 They are 19 addresses in the pool and two have been allocated. 75 00:07:36,150 --> 00:07:44,540 So this would be another good command to use Let's clear the net translation and remove the command 76 00:07:50,290 --> 00:07:58,680 and I'll add it back with only a single IP address in the poll. 77 00:07:59,890 --> 00:08:11,470 So show IP not translations no translations at the moment show IP that statistics notice we only have 78 00:08:11,470 --> 00:08:13,570 one IP address in the pool. 79 00:08:13,600 --> 00:08:15,220 So when rodders three pings 80 00:08:18,020 --> 00:08:25,510 and we look at the statistics again notice 100 percent of the polies allocated. 81 00:08:25,560 --> 00:08:27,220 So that's why I wrote it too. 82 00:08:27,360 --> 00:08:34,740 He's not able to ping because the because the pool consists of a single IP address and it's already 83 00:08:34,740 --> 00:08:36,750 been allocated. 84 00:08:36,760 --> 00:08:39,150 So again be careful with your polls. 85 00:08:40,320 --> 00:08:46,330 You need to allocate enough addresses to the poll so clear the net translations again. 86 00:08:51,680 --> 00:09:09,030 All remove that poll configure it again with let's say from 2 to 25 to show IP not statistics. 87 00:09:10,800 --> 00:09:19,320 We have 24 addresses in the poll in this range none have been allocated since some traffic from both 88 00:09:19,320 --> 00:09:24,550 wrote to and registry. 89 00:09:24,760 --> 00:09:29,200 So we can see that rodded is being Nottage and so is lot a three. 90 00:09:29,370 --> 00:09:37,020 And now when we look at the statistics noticed 24 addresses are available to have been allocated. 91 00:09:37,500 --> 00:09:44,100 So that was an example of how to troubleshoot network address translation on net Oakie found the video 92 00:09:44,100 --> 00:09:50,640 useful if you enjoyed it please like it and please subscribe to my YouTube channel. 93 00:09:50,640 --> 00:09:52,590 I wish you all the very best.