1 00:00:11,960 --> 00:00:18,380 This is one of multiple LAN local area network troubleshooting videos. 2 00:00:18,380 --> 00:00:27,950 In this example users are complaining that PC one can't ping the PC to his Rodda one acting as PC one 3 00:00:28,750 --> 00:00:31,070 paying $10 one the sweet or two. 4 00:00:32,070 --> 00:00:34,930 Looks like that pings or failing. 5 00:00:35,060 --> 00:00:46,490 So we don't have connectivity from PC one PC to show IP ront default gateway of the PC is configured 6 00:00:47,030 --> 00:00:49,920 to 10 to 1 2 2 2 2 5 4. 7 00:00:49,910 --> 00:01:00,710 This is a subscriber is Virata But IP routing has been disabled hence the writing table looks as follows. 8 00:01:01,610 --> 00:01:10,110 IP writing is disabled but a default gateway has been configured. 9 00:01:10,110 --> 00:01:14,420 Hence we see default gateway as follows. 10 00:01:14,460 --> 00:01:17,190 Can we ping the default gateway. 11 00:01:17,490 --> 00:01:25,820 Yes we can can be paying villans 3 on the Default Gateway PC 2 is in violent 3. 12 00:01:25,990 --> 00:01:29,900 And notice here is the default gateway so which one. 13 00:01:30,210 --> 00:01:33,850 Some of the documentation and this topology hasn't been updated. 14 00:01:33,960 --> 00:01:39,010 And that's something you constantly going to find when troubleshooting real networks. 15 00:01:39,210 --> 00:01:44,220 So we can ping villans 3 on the default gateway. 16 00:01:44,380 --> 00:01:53,850 Can the default gateway ping router to see just switch one acting as the default gateway Kennet paying 17 00:01:53,850 --> 00:01:59,270 10.0 one two or three to two. 18 00:01:59,270 --> 00:02:00,470 No it can't. 19 00:02:00,470 --> 00:02:06,350 So it looks like we have a problem between switch one and this router. 20 00:02:06,440 --> 00:02:11,900 Let's check if we have connectivity between the access switch and the core switch. 21 00:02:13,050 --> 00:02:16,620 My typologies not showing the IP address of the access switch. 22 00:02:16,620 --> 00:02:23,210 So let's jump onto the access switch and confirm and check what it's IP addresses. 23 00:02:23,330 --> 00:02:29,900 This is a problem you may encounter if you don't have no IP domain lookup enabled these devices are 24 00:02:30,050 --> 00:02:38,900 always very layer 2 switches and routers ingenius 3 no IP domain lookup is not enabled by default on 25 00:02:38,900 --> 00:02:40,140 these devices. 26 00:02:40,190 --> 00:02:45,100 So that's probably something we want to do immediately to save us. 27 00:02:45,110 --> 00:02:47,600 Frustration. 28 00:02:47,640 --> 00:02:58,800 So the command is no IP domain look up say show IP interface brief which has this IP address from Villon 29 00:02:58,800 --> 00:03:06,050 one can we paying the cost switch on villaine one looks like we can't. 30 00:03:06,320 --> 00:03:10,890 Can we ping the score switch. 31 00:03:11,030 --> 00:03:12,770 Switch to. 32 00:03:12,970 --> 00:03:16,350 So before going any further let's update the documentation. 33 00:03:16,360 --> 00:03:18,740 That's the IP address of the switch. 34 00:03:18,760 --> 00:03:27,000 Let's check if the switch can paying switch to switch to show on the interface. 35 00:03:27,010 --> 00:03:32,180 Brief OK it has IP addresses on the three villans. 36 00:03:32,200 --> 00:03:36,270 So what I'll do is update the diagram. 37 00:03:36,610 --> 00:03:47,680 It's 2 5 3 in all the violence that's IP addresses off switch to can switch for the access switch paying 38 00:03:49,380 --> 00:03:49,860 $10. 39 00:03:49,870 --> 00:03:52,300 1 1 2 5 3. 40 00:03:52,630 --> 00:03:53,730 Doesn't look like it can. 41 00:03:53,730 --> 00:04:01,410 So it looks like there's a problem on the link between switch to and switch for show CTP neighbor. 42 00:04:01,650 --> 00:04:10,720 We do see a neighbor relationship between the local switch and router 2 as well as switch to shows on 43 00:04:10,730 --> 00:04:11,390 the interface. 44 00:04:11,390 --> 00:04:22,010 Brief interfaces look up show interface trunk. 45 00:04:22,080 --> 00:04:26,140 It looks like interfaces trunking to the core. 46 00:04:26,430 --> 00:04:38,800 Let's check the configuration on the cost which so show interface trunk can you see the problem. 47 00:04:38,840 --> 00:04:44,250 What I'll do is move the console to the left chair can you see the issue. 48 00:04:44,610 --> 00:04:52,020 What's the problem between switch to and switch full. 49 00:04:52,030 --> 00:04:59,820 OK so on switch for gigabit to 0 0 has trunking on being kept solution is a two to one. 50 00:04:59,820 --> 00:05:08,360 Q native villain is one on gigabit zero one on switch to trunking is on. 51 00:05:08,880 --> 00:05:16,990 But the encapsulation is Eisele so trunking is enabled with a native villain of one but the encapsulation 52 00:05:17,140 --> 00:05:20,540 is wrong or different. 53 00:05:20,550 --> 00:05:27,790 So encapsulation is Eisele on this port where as on the port and cancellation is dot one. 54 00:05:27,790 --> 00:05:34,400 Q You need to have the same encapsulation of both sides. 55 00:05:34,460 --> 00:05:41,710 So what I'll do is change the encapsulation show run interface gigabits for one that looks better. 56 00:05:44,320 --> 00:05:58,290 Kand the switch now paying switch for with IP address 10 1 1 4 it still hasn't come up. 57 00:05:58,370 --> 00:06:03,850 What we may have to do is wait a bit but what I'll do just to force things is shut the interface down 58 00:06:05,180 --> 00:06:08,560 and then no shut it. 59 00:06:08,740 --> 00:06:13,870 You may have a slightly different experience engine history versus a physical switch. 60 00:06:15,880 --> 00:06:20,290 We still only see switch one through CTP that may take a while to come up. 61 00:06:24,090 --> 00:06:32,590 Faces up up show interface trunk trunking is now set to edit to the one cume both sites. 62 00:06:32,660 --> 00:06:38,890 Can this switch now paying switch to use it can. 63 00:06:39,070 --> 00:06:40,330 So that looks better. 64 00:06:41,390 --> 00:06:47,540 If you have issues you may want to shut and then shut the interface so that the encapsulation and other 65 00:06:47,540 --> 00:06:49,210 options are renegotiated. 66 00:06:50,390 --> 00:06:56,390 Second PC one ping PC to check if that works. 67 00:06:58,270 --> 00:07:00,030 OK we still have a problem. 68 00:07:01,100 --> 00:07:12,970 PC one on the left is not able to ping PC to let's do a trace to 10 1 3 2 so it gets to the default 69 00:07:13,000 --> 00:07:22,570 gateway and then the trace times out can PC to Rodda to acting as PC to ping its default gateway 70 00:07:25,560 --> 00:07:26,350 Yes it can 71 00:07:29,170 --> 00:07:32,140 noticed suddenly here we had some kind of put 72 00:07:38,210 --> 00:07:43,610 and I was actually running an ICMP debug here and noticed the output. 73 00:07:43,770 --> 00:07:45,520 So let's try to do that ping again. 74 00:07:47,440 --> 00:07:52,310 And what I'll do is enable a debug MP 75 00:07:55,030 --> 00:07:59,350 So the pings are suddenly working and that may be a genius 3. 76 00:07:59,350 --> 00:08:02,680 The problem here is notice this option. 77 00:08:02,770 --> 00:08:09,400 Be careful especially with PCs you may have a problem where everything looks good but the PCs can't 78 00:08:09,400 --> 00:08:11,180 ping each other. 79 00:08:11,200 --> 00:08:21,010 What I should have configured is an IP default gateway of 10 to 1 or 3 or 5 for. 80 00:08:21,100 --> 00:08:23,920 So in a real environment that ping may not work. 81 00:08:23,920 --> 00:08:26,770 It depends where the proxy arp is enabled on your will. 82 00:08:26,980 --> 00:08:36,360 In TV land routing devices proxy up will allow a device to proxy the default gateways of other devices. 83 00:08:36,440 --> 00:08:43,830 In many cases that's disabled so you need to have the default gateways enabled on both sides. 84 00:08:43,840 --> 00:08:53,000 The IP route notice default gateway show IP Raat default gateway is configured so be careful in a real 85 00:08:53,000 --> 00:09:00,320 environment and in the exam that the default Gateway's on both age devices are configured properly. 86 00:09:00,570 --> 00:09:03,080 So we've not fixed the apology. 87 00:09:03,210 --> 00:09:08,600 If you enjoyed the video please like it please subscribe to my YouTube channel. 88 00:09:08,640 --> 00:09:10,110 I wish you all the very best.