[Script Info] Title: [Events] Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text Dialogue: 0,0:00:00.12,0:00:02.56,Default,,0000,0000,0000,,and welcome back not every Journey to Dialogue: 0,0:00:02.56,0:00:04.28,Default,,0000,0000,0000,,the world of troubleshooting ends the Dialogue: 0,0:00:04.28,0:00:05.96,Default,,0000,0000,0000,,same way some things are easier to Dialogue: 0,0:00:05.96,0:00:07.80,Default,,0000,0000,0000,,troubleshoot than others and also if you Dialogue: 0,0:00:07.80,0:00:09.72,Default,,0000,0000,0000,,and I've been working on like one large Dialogue: 0,0:00:09.72,0:00:11.24,Default,,0000,0000,0000,,Network we know it like the back of our Dialogue: 0,0:00:11.24,0:00:13.44,Default,,0000,0000,0000,,hand it's a lot easier to troubleshoot Dialogue: 0,0:00:13.44,0:00:14.84,Default,,0000,0000,0000,,because we know what the subnets are and Dialogue: 0,0:00:14.84,0:00:16.80,Default,,0000,0000,0000,,the interfaces involved where on the Dialogue: 0,0:00:16.80,0:00:17.92,Default,,0000,0000,0000,,other hand if we go to a brand new Dialogue: 0,0:00:17.92,0:00:19.92,Default,,0000,0000,0000,,network or we're doing consulting it may Dialogue: 0,0:00:19.92,0:00:21.96,Default,,0000,0000,0000,,take some warm-up time to get used to Dialogue: 0,0:00:21.96,0:00:24.00,Default,,0000,0000,0000,,and to figure out where everything is on Dialogue: 0,0:00:24.00,0:00:26.00,Default,,0000,0000,0000,,that specific customers Network and when Dialogue: 0,0:00:26.00,0:00:27.28,Default,,0000,0000,0000,,we're doing troubleshooting again Dialogue: 0,0:00:27.28,0:00:28.60,Default,,0000,0000,0000,,whether it's our own network that we Dialogue: 0,0:00:28.60,0:00:30.24,Default,,0000,0000,0000,,know really well or it's a new Network Dialogue: 0,0:00:30.24,0:00:31.76,Default,,0000,0000,0000,,that we were just introduced to if we Dialogue: 0,0:00:31.76,0:00:33.52,Default,,0000,0000,0000,,have a certain process or methodology Dialogue: 0,0:00:33.52,0:00:35.36,Default,,0000,0000,0000,,for troubleshooting we can apply that Dialogue: 0,0:00:35.36,0:00:37.76,Default,,0000,0000,0000,,methodology across the board so let's Dialogue: 0,0:00:37.76,0:00:38.84,Default,,0000,0000,0000,,have some fun with this we'll put an Dialogue: 0,0:00:38.84,0:00:40.16,Default,,0000,0000,0000,,overview of the high level steps Dialogue: 0,0:00:40.16,0:00:41.96,Default,,0000,0000,0000,,regarding a troubleshooting methodology Dialogue: 0,0:00:41.96,0:00:43.80,Default,,0000,0000,0000,,and then as we proceed together we'll Dialogue: 0,0:00:43.80,0:00:45.68,Default,,0000,0000,0000,,actually apply those steps as we Dialogue: 0,0:00:45.68,0:00:48.04,Default,,0000,0000,0000,,troubleshoot together a network so the Dialogue: 0,0:00:48.04,0:00:49.36,Default,,0000,0000,0000,,very beginning of this troubleshooting Dialogue: 0,0:00:49.36,0:00:51.92,Default,,0000,0000,0000,,process it would be to identify the Dialogue: 0,0:00:51.92,0:00:53.72,Default,,0000,0000,0000,,problem case in point let's imagine that Dialogue: 0,0:00:53.72,0:00:55.32,Default,,0000,0000,0000,,the user who's sitting at this computer Dialogue: 0,0:00:55.32,0:00:57.56,Default,,0000,0000,0000,,right here pc10 calls the service desk Dialogue: 0,0:00:57.56,0:00:58.64,Default,,0000,0000,0000,,or the help desk or whatever they're Dialogue: 0,0:00:58.64,0:01:00.36,Default,,0000,0000,0000,,calling it in your organization and they Dialogue: 0,0:01:00.36,0:01:02.44,Default,,0000,0000,0000,,say yeah I've got a problem and then the Dialogue: 0,0:01:02.44,0:01:04.44,Default,,0000,0000,0000,,service desk says okay tell me more and Dialogue: 0,0:01:04.44,0:01:05.80,Default,,0000,0000,0000,,if the user says well I can't really Dialogue: 0,0:01:05.80,0:01:08.36,Default,,0000,0000,0000,,tell you anything well we have to kind Dialogue: 0,0:01:08.36,0:01:10.24,Default,,0000,0000,0000,,of you know narrow down what the problem Dialogue: 0,0:01:10.24,0:01:12.08,Default,,0000,0000,0000,,is or at least get what the symptoms are Dialogue: 0,0:01:12.08,0:01:13.20,Default,,0000,0000,0000,,and that's why one of the very first Dialogue: 0,0:01:13.20,0:01:14.92,Default,,0000,0000,0000,,steps is to identify the problems so Dialogue: 0,0:01:14.92,0:01:16.24,Default,,0000,0000,0000,,with the identification of the problem Dialogue: 0,0:01:16.24,0:01:18.28,Default,,0000,0000,0000,,the user may say I can't access the Dialogue: 0,0:01:18.28,0:01:19.56,Default,,0000,0000,0000,,internet or they may just say the Dialogue: 0,0:01:19.56,0:01:21.16,Default,,0000,0000,0000,,network is down at which point we would Dialogue: 0,0:01:21.16,0:01:23.04,Default,,0000,0000,0000,,ask some additional questions so let's Dialogue: 0,0:01:23.04,0:01:24.84,Default,,0000,0000,0000,,imagine this user says that I can't Dialogue: 0,0:01:24.84,0:01:26.84,Default,,0000,0000,0000,,access anything on the internet that Dialogue: 0,0:01:26.84,0:01:28.20,Default,,0000,0000,0000,,would fall into this category of Dialogue: 0,0:01:28.20,0:01:29.48,Default,,0000,0000,0000,,identifying the problem is that this Dialogue: 0,0:01:29.48,0:01:31.28,Default,,0000,0000,0000,,user who normally can access the Dialogue: 0,0:01:31.28,0:01:32.96,Default,,0000,0000,0000,,internet can no longer access the Dialogue: 0,0:01:32.96,0:01:34.88,Default,,0000,0000,0000,,internet the Second Step would be to Dialogue: 0,0:01:34.88,0:01:37.28,Default,,0000,0000,0000,,establish a theory Regarding why that Dialogue: 0,0:01:37.28,0:01:39.00,Default,,0000,0000,0000,,might be happening and so by leveraging Dialogue: 0,0:01:39.00,0:01:41.24,Default,,0000,0000,0000,,a topology like this we could ask Dialogue: 0,0:01:41.24,0:01:43.04,Default,,0000,0000,0000,,ourselves a few questions for example is Dialogue: 0,0:01:43.04,0:01:45.72,Default,,0000,0000,0000,,this computer powered on uh if the Dialogue: 0,0:01:45.72,0:01:47.12,Default,,0000,0000,0000,,computer is powered on does it have an Dialogue: 0,0:01:47.12,0:01:49.48,Default,,0000,0000,0000,,IP address and if it's a DHCP client did Dialogue: 0,0:01:49.48,0:01:51.08,Default,,0000,0000,0000,,it get the right information regarding a Dialogue: 0,0:01:51.08,0:01:52.88,Default,,0000,0000,0000,,default gateway and the subnet and all Dialogue: 0,0:01:52.88,0:01:54.88,Default,,0000,0000,0000,,that good stuff and then regarding this Dialogue: 0,0:01:54.88,0:01:56.84,Default,,0000,0000,0000,,port is this port on the switch is it Dialogue: 0,0:01:56.84,0:01:58.36,Default,,0000,0000,0000,,associated with the right VLAN which is Dialogue: 0,0:01:58.36,0:02:00.36,Default,,0000,0000,0000,,VLAN 10 and regarding the the trunking Dialogue: 0,0:02:00.36,0:02:01.64,Default,,0000,0000,0000,,that's going down from the axxis layer Dialogue: 0,0:02:01.64,0:02:04.08,Default,,0000,0000,0000,,switch to the core is trunking working Dialogue: 0,0:02:04.08,0:02:05.96,Default,,0000,0000,0000,,and is VLAN 10 being allowed and then Dialogue: 0,0:02:05.96,0:02:07.88,Default,,0000,0000,0000,,from the default gateways perspective Dialogue: 0,0:02:07.88,0:02:09.88,Default,,0000,0000,0000,,regarding VLAN 10 Who's acting is the Dialogue: 0,0:02:09.88,0:02:11.84,Default,,0000,0000,0000,,default gateway is it Core 1 or Core 2 Dialogue: 0,0:02:11.84,0:02:13.08,Default,,0000,0000,0000,,or are they using a first toop Dialogue: 0,0:02:13.08,0:02:15.00,Default,,0000,0000,0000,,redundancy protocol and if so which one Dialogue: 0,0:02:15.00,0:02:16.96,Default,,0000,0000,0000,,of these two devices is acting as the Dialogue: 0,0:02:16.96,0:02:18.88,Default,,0000,0000,0000,,active device and does that device Dialogue: 0,0:02:18.88,0:02:20.56,Default,,0000,0000,0000,,acting as the default gateway have a Dialogue: 0,0:02:20.56,0:02:22.60,Default,,0000,0000,0000,,route out towards the internet in simple Dialogue: 0,0:02:22.60,0:02:24.24,Default,,0000,0000,0000,,terms does it know how to forward and Dialogue: 0,0:02:24.24,0:02:25.48,Default,,0000,0000,0000,,the same thing would hold true for this Dialogue: 0,0:02:25.48,0:02:27.92,Default,,0000,0000,0000,,router and then this connectivity to our Dialogue: 0,0:02:27.92,0:02:29.60,Default,,0000,0000,0000,,service provider and also because we're Dialogue: 0,0:02:29.60,0:02:31.12,Default,,0000,0000,0000,,us rfc1918 Dialogue: 0,0:02:31.12,0:02:33.16,Default,,0000,0000,0000,,addresses perhaps Network address Dialogue: 0,0:02:33.16,0:02:34.96,Default,,0000,0000,0000,,translation is failing or isn't Dialogue: 0,0:02:34.96,0:02:37.00,Default,,0000,0000,0000,,implemented correctly so if this user a Dialogue: 0,0:02:37.00,0:02:39.68,Default,,0000,0000,0000,,pc10 by doing a few tests we verify that Dialogue: 0,0:02:39.68,0:02:41.64,Default,,0000,0000,0000,,it can ping its default gateway and if Dialogue: 0,0:02:41.64,0:02:43.08,Default,,0000,0000,0000,,this device in vant up here at Dialogue: 0,0:02:43.08,0:02:45.04,Default,,0000,0000,0000,,headquarters can ping devices out here Dialogue: 0,0:02:45.04,0:02:46.48,Default,,0000,0000,0000,,at site 2 and site 3 and has Dialogue: 0,0:02:46.48,0:02:48.12,Default,,0000,0000,0000,,reachability there that can help Dialogue: 0,0:02:48.12,0:02:50.04,Default,,0000,0000,0000,,identify what is working and then we Dialogue: 0,0:02:50.04,0:02:51.48,Default,,0000,0000,0000,,could establish a theory about what may Dialogue: 0,0:02:51.48,0:02:53.44,Default,,0000,0000,0000,,be specifically causing the problem and Dialogue: 0,0:02:53.44,0:02:54.88,Default,,0000,0000,0000,,then once we've narrowed it down to what Dialogue: 0,0:02:54.88,0:02:56.84,Default,,0000,0000,0000,,we think it might be and then the third Dialogue: 0,0:02:56.84,0:02:58.88,Default,,0000,0000,0000,,step is to test which is to basically go Dialogue: 0,0:02:58.88,0:03:00.68,Default,,0000,0000,0000,,in and prove your theory if we think the Dialogue: 0,0:03:00.68,0:03:03.12,Default,,0000,0000,0000,,problem is with router one or if we Dialogue: 0,0:03:03.12,0:03:04.12,Default,,0000,0000,0000,,think the problem was with the Dialogue: 0,0:03:04.12,0:03:05.52,Default,,0000,0000,0000,,multi-layer switch or we think the Dialogue: 0,0:03:05.52,0:03:07.12,Default,,0000,0000,0000,,problem was with the axis layer we want Dialogue: 0,0:03:07.12,0:03:09.08,Default,,0000,0000,0000,,to do some testing to validate that what Dialogue: 0,0:03:09.08,0:03:10.84,Default,,0000,0000,0000,,we think may be the problem really is Dialogue: 0,0:03:10.84,0:03:12.60,Default,,0000,0000,0000,,causing the problem and then once we've Dialogue: 0,0:03:12.60,0:03:14.32,Default,,0000,0000,0000,,narrowed it down and verified it we then Dialogue: 0,0:03:14.32,0:03:16.76,Default,,0000,0000,0000,,want to go ahead and solve the problem Dialogue: 0,0:03:16.76,0:03:19.32,Default,,0000,0000,0000,,now solving the problem uh in an Dialogue: 0,0:03:19.32,0:03:21.92,Default,,0000,0000,0000,,organization also has many steps Dialogue: 0,0:03:21.92,0:03:23.60,Default,,0000,0000,0000,,involved with it let's list a few of Dialogue: 0,0:03:23.60,0:03:25.88,Default,,0000,0000,0000,,those as far as the solution to this Dialogue: 0,0:03:25.88,0:03:27.24,Default,,0000,0000,0000,,network connectivity problem that the Dialogue: 0,0:03:27.24,0:03:29.24,Default,,0000,0000,0000,,user is having out to the internet and Dialogue: 0,0:03:29.24,0:03:31.56,Default,,0000,0000,0000,,let's also imagine based on our testing Dialogue: 0,0:03:31.56,0:03:32.88,Default,,0000,0000,0000,,that we believe it's an issue with Dialogue: 0,0:03:32.88,0:03:35.24,Default,,0000,0000,0000,,address translation which could be natat Dialogue: 0,0:03:35.24,0:03:37.56,Default,,0000,0000,0000,,or Pat but definitely needs to happen at Dialogue: 0,0:03:37.56,0:03:39.48,Default,,0000,0000,0000,,some point before that traffic goes out Dialogue: 0,0:03:39.48,0:03:41.12,Default,,0000,0000,0000,,to the Internet so if we've done some Dialogue: 0,0:03:41.12,0:03:42.40,Default,,0000,0000,0000,,testing and we've narrowed it down that Dialogue: 0,0:03:42.40,0:03:44.12,Default,,0000,0000,0000,,it is an address translation issue Dialogue: 0,0:03:44.12,0:03:45.96,Default,,0000,0000,0000,,regarding solving that we' want to Dialogue: 0,0:03:45.96,0:03:48.72,Default,,0000,0000,0000,,create a game plan on exactly how we are Dialogue: 0,0:03:48.72,0:03:50.64,Default,,0000,0000,0000,,going to solve that problem perhaps with Dialogue: 0,0:03:50.64,0:03:52.44,Default,,0000,0000,0000,,network address translation the N device Dialogue: 0,0:03:52.44,0:03:54.96,Default,,0000,0000,0000,,was set up to support vlen 20 with the Dialogue: 0,0:03:54.96,0:03:57.52,Default,,0000,0000,0000,,10120 subnet and other networks like Dialogue: 0,0:03:57.52,0:03:59.20,Default,,0000,0000,0000,,this over here at site 2 and site three Dialogue: 0,0:03:59.20,0:04:01.20,Default,,0000,0000,0000,,but maybe perhaps not including the Dialogue: 0,0:04:01.20,0:04:03.76,Default,,0000,0000,0000,,10.10 subnet so we want to make a plan Dialogue: 0,0:04:03.76,0:04:05.72,Default,,0000,0000,0000,,to correct that and also in corporations Dialogue: 0,0:04:05.72,0:04:06.88,Default,,0000,0000,0000,,that's going to involve going through Dialogue: 0,0:04:06.88,0:04:08.52,Default,,0000,0000,0000,,Change Control if we're going to make a Dialogue: 0,0:04:08.52,0:04:10.44,Default,,0000,0000,0000,,configuration change and then with the Dialogue: 0,0:04:10.44,0:04:12.08,Default,,0000,0000,0000,,authorization from the Change Control Dialogue: 0,0:04:12.08,0:04:13.52,Default,,0000,0000,0000,,Board then we're going to go ahead and Dialogue: 0,0:04:13.52,0:04:15.32,Default,,0000,0000,0000,,implement the change and then when we've Dialogue: 0,0:04:15.32,0:04:16.88,Default,,0000,0000,0000,,implemented it we also want to verify Dialogue: 0,0:04:16.88,0:04:18.56,Default,,0000,0000,0000,,that it's working and that verification Dialogue: 0,0:04:18.56,0:04:20.00,Default,,0000,0000,0000,,would involve a few things number one Dialogue: 0,0:04:20.00,0:04:21.52,Default,,0000,0000,0000,,that we now have connectivity from this Dialogue: 0,0:04:21.52,0:04:24.04,Default,,0000,0000,0000,,PC out to the internet also we'd want to Dialogue: 0,0:04:24.04,0:04:26.24,Default,,0000,0000,0000,,verify that we didn't make any other Dialogue: 0,0:04:26.24,0:04:28.36,Default,,0000,0000,0000,,changes that would negatively impact our Dialogue: 0,0:04:28.36,0:04:29.76,Default,,0000,0000,0000,,environment like we want to make sure Dialogue: 0,0:04:29.76,0:04:31.32,Default,,0000,0000,0000,,everything else still functions as well Dialogue: 0,0:04:31.32,0:04:33.48,Default,,0000,0000,0000,,v20 and the other sites everything can Dialogue: 0,0:04:33.48,0:04:35.00,Default,,0000,0000,0000,,still forward out to the internet and Dialogue: 0,0:04:35.00,0:04:36.20,Default,,0000,0000,0000,,then we'd also want to make sure we Dialogue: 0,0:04:36.20,0:04:38.96,Default,,0000,0000,0000,,document the solution what we did how we Dialogue: 0,0:04:38.96,0:04:41.04,Default,,0000,0000,0000,,did it and if we changed the topology in Dialogue: 0,0:04:41.04,0:04:42.88,Default,,0000,0000,0000,,some fashion we'd want to include that Dialogue: 0,0:04:42.88,0:04:45.04,Default,,0000,0000,0000,,update in our documentation so the Dialogue: 0,0:04:45.04,0:04:46.84,Default,,0000,0000,0000,,documentation of what was done and also Dialogue: 0,0:04:46.84,0:04:48.52,Default,,0000,0000,0000,,the topology if there's been updates Dialogue: 0,0:04:48.52,0:04:50.60,Default,,0000,0000,0000,,that's super important because let's say Dialogue: 0,0:04:50.60,0:04:52.72,Default,,0000,0000,0000,,3 or four days go by and we have yet Dialogue: 0,0:04:52.72,0:04:54.72,Default,,0000,0000,0000,,another problem and we think oh I wonder Dialogue: 0,0:04:54.72,0:04:57.28,Default,,0000,0000,0000,,if what we changed here injected Dialogue: 0,0:04:57.28,0:04:58.92,Default,,0000,0000,0000,,additional problems into the network so Dialogue: 0,0:04:58.92,0:05:00.36,Default,,0000,0000,0000,,we could go back through our paper trail Dialogue: 0,0:05:00.36,0:05:02.24,Default,,0000,0000,0000,,and identify what happened when it Dialogue: 0,0:05:02.24,0:05:03.96,Default,,0000,0000,0000,,happened what was changed and that can Dialogue: 0,0:05:03.96,0:05:05.12,Default,,0000,0000,0000,,help speed up our troubleshooting Dialogue: 0,0:05:05.12,0:05:07.52,Default,,0000,0000,0000,,because a lot of times uh there are Dialogue: 0,0:05:07.52,0:05:09.08,Default,,0000,0000,0000,,cabling issues and physical issues and Dialogue: 0,0:05:09.08,0:05:10.88,Default,,0000,0000,0000,,so forth but a lot of times when Dialogue: 0,0:05:10.88,0:05:12.56,Default,,0000,0000,0000,,something breaks on the network when Dialogue: 0,0:05:12.56,0:05:14.92,Default,,0000,0000,0000,,something stops working it's quite often Dialogue: 0,0:05:14.92,0:05:17.52,Default,,0000,0000,0000,,due to the last change that was made and Dialogue: 0,0:05:17.52,0:05:18.80,Default,,0000,0000,0000,,so if we go back and take a look at the Dialogue: 0,0:05:18.80,0:05:20.52,Default,,0000,0000,0000,,last change or two that can help us Dialogue: 0,0:05:20.52,0:05:22.40,Default,,0000,0000,0000,,reduce our troubleshooting Time by Dialogue: 0,0:05:22.40,0:05:23.92,Default,,0000,0000,0000,,either confirming that what was done is Dialogue: 0,0:05:23.92,0:05:26.36,Default,,0000,0000,0000,,not impacting our current problem or by Dialogue: 0,0:05:26.36,0:05:28.76,Default,,0000,0000,0000,,verifying that what was done indeed is Dialogue: 0,0:05:28.76,0:05:30.52,Default,,0000,0000,0000,,impacting our current Network and then Dialogue: 0,0:05:30.52,0:05:32.88,Default,,0000,0000,0000,,the last step here is to go ahead and Dialogue: 0,0:05:32.88,0:05:35.64,Default,,0000,0000,0000,,repeat this process for the next Dialogue: 0,0:05:35.64,0:05:37.88,Default,,0000,0000,0000,,problem so the next servers call that Dialogue: 0,0:05:37.88,0:05:40.28,Default,,0000,0000,0000,,comes in the next issue the next problem Dialogue: 0,0:05:40.28,0:05:41.88,Default,,0000,0000,0000,,again we're going to follow this logical Dialogue: 0,0:05:41.88,0:05:43.68,Default,,0000,0000,0000,,plan so what I think would be fun to do Dialogue: 0,0:05:43.68,0:05:45.80,Default,,0000,0000,0000,,is let's take this network topology Dialogue: 0,0:05:45.80,0:05:47.16,Default,,0000,0000,0000,,which we've been playing on and off with Dialogue: 0,0:05:47.16,0:05:48.84,Default,,0000,0000,0000,,throughout these videos and what I'll do Dialogue: 0,0:05:48.84,0:05:50.80,Default,,0000,0000,0000,,is I will inject a problem somewhere in Dialogue: 0,0:05:50.80,0:05:52.44,Default,,0000,0000,0000,,this mix and then we can go through Dialogue: 0,0:05:52.44,0:05:53.88,Default,,0000,0000,0000,,these steps one at a time in this Dialogue: 0,0:05:53.88,0:05:55.96,Default,,0000,0000,0000,,troubleshooting methodology and as we do Dialogue: 0,0:05:55.96,0:05:57.72,Default,,0000,0000,0000,,so we'll go into more details on each Dialogue: 0,0:05:57.72,0:05:59.80,Default,,0000,0000,0000,,one so in the very next video join me as Dialogue: 0,0:05:59.80,0:06:01.60,Default,,0000,0000,0000,,we take a look at this first stage in Dialogue: 0,0:06:01.60,0:06:03.40,Default,,0000,0000,0000,,the troubleshooting methodology and that Dialogue: 0,0:06:03.40,0:06:05.24,Default,,0000,0000,0000,,is identifying the problem which we'll Dialogue: 0,0:06:05.24,0:06:07.40,Default,,0000,0000,0000,,do in this network topology so I'll see Dialogue: 0,0:06:07.40,0:06:10.00,Default,,0000,0000,0000,,you in that video in just a moment hey Dialogue: 0,0:06:10.00,0:06:11.60,Default,,0000,0000,0000,,thanks for watching And subscribe right Dialogue: 0,0:06:11.60,0:06:13.44,Default,,0000,0000,0000,,here to get the latest information from Dialogue: 0,0:06:13.44,0:06:15.52,Default,,0000,0000,0000,,CBT Nuggets and if you're new to or Dialogue: 0,0:06:15.52,0:06:17.44,Default,,0000,0000,0000,,considering a career in the world of it Dialogue: 0,0:06:17.44,0:06:19.28,Default,,0000,0000,0000,,head on over to CBT Nuggets and sign up Dialogue: 0,0:06:19.28,0:06:22.84,Default,,0000,0000,0000,,for a free trial