CCNP ENARSI - 1.1 Troubleshoot Administrative Distance (all routing protocols) - LAB

okay so welcome to the lab environment as you can potentially tell i'm using gns3 for my labbing environments you can use whatever you like but i highly recommend using something that emulates cisco ios versus something that simulates cisco ios so packet tracer for example is a simulator and so because it simulates it can actually behave differently to how cisco ios will actually behave gns3 allows you to use emulation of cisco ios so it behaves exactly as cisco ios does so that's the reason i'm using gns3 but you can use whatever you like all right so just to give you an overview of what we're going to go through is i'm going to actually go through the full configuration from scratch so if you want to skip that timestamp on screen now to allow you to skip forward to when we start troubleshooting the admin distances but for those that want to see the full configuration stay tuned because we're going to get started right now okay so let's just drag in a few routers and that's all we're going to be using in here are some routers for this lab i'm going to use four routers in total so i'm going to drag these across here and it's going to rename them to something a little bit more meaningful to us because at the moment don't really like the names that they're given so r3 and r4 down here excellent and then we're going to add a link between each one so we're going to go from 0 0 0 0 0 1 to 0 1 and finally 0 2 to 0 2. noting here i've got ethernet as my interface name so i specify these with e 0 0. they're all connected so click start if you're following along in gns3 and now i'm going to start writing out my configs now i'm actually going to use a text editor to write out my configs just to make it easier to copy across between devices so we'll start with enable and configure terminal and then i'm going to specify my hostname so for r1 is what we're going to be working on first and then no ip domain lookup just so if we have any typos you have to wait for that and now let's get cracking straight into the interface so e0 is what i'm configuring here on r1 and just going to go to set the ip address now for this r1 to r2 connection we're using ospf and this is the network statement here so for each device the final octet is just going to match the number of the router so this interface here is 172.201. so 172.20.0.1 and of course put in the subnet mask being a slash 24 subnet mask we're then going to enable that interface oops and that's it for that interface now each into each router is also going to have at least one loopback interface so loop back zero or if you want to make writer even shorter lo zero that's loopback zero give this an ip address of 101.1.1 and it's going to use all of the bits in the subnet mask no chart and then we can move on to the osbf definition so ospf process so i'm going to use process number one and now we need to advertise our network so i'm going to advertise the 172.20 network and then the wildcard mask so because of slash24 and now we put in the area statement at the end don't forget that crucial part now that's not all we also have another network statement that we need to put in here because we're using that loopback we want to advertise that through to our neighbor or spf neighbors if we had plural and obvious that's how the wildcard mask is going to be set and same thing area 0. and that's actually it that's it for router 1 for now at least so just configuring the basic things you can either double click or right click and click console to bring up the console session and i press enter a few times just to clear the screen a little bit and then right click to paste in so it's pasted in all of the things that i entered before and we can see here let me just expand this out a little bit it has changed loopback 0 is up ethernet 0 0 is up and that's basically it that's all we expect so far so let's move on to router 2. so i'm just going to keep this copy and paste and just change it for router 2. so hostname is r2 and same interface e0 but this is going to change to dot two loop back zero zero that's fine we'll keep it a zero zero but we'll obviously change this to a different number so two two two two for router two process id can stay the same for ospf network statement can stay the same for this network but we want to advertise our loopback interface not router one's loopback interface and that's it done so that's why we're using a text editor makes things a hell of a lot faster now if i go into r2 spam that a few times right click it's pasted everything in now hopefully we'll see something a little bit different this time sorry i had to press enter and loop back 0 is up ethernet 0 0 is up and now we can see this ospf message so it's a notification message level five process one on this neighbor so this is the ospf id which r1 has taken from the loopback interface address so if you don't specify that's where it gets it from and it's gone from loading to full excellent so now we've got an ospf neighbor adjacency awesome now let's continue on with the configuration so let's go to r3 so i'm going to move this across to this side now just so we can see what we're working with on the other side i'm still going to copy this and paste it in here but it's going to change a few more things this time so i'm going to change that to r3 and you also might have noticed that these already had the correct name so as soon as i press enter it already had r2 and the reason it really had that name is because i changed the name here before i turned these devices on and so that's the name that it takes when it starts just if you're wondering so back to r3's configuration we're no longer using this interface we're using zero one because this is zero one and this is zero one and this iop address is now completely incorrect we're using eigrp and this network on this side so for r3 it's going to be 100.3 still a slash 24 though now we're going to change this just to all threes and this can now be completely deleted so we're not using router ospf we are using router ergrp and we'll just use the classic ergarp so we're going to specify the autonomous system number 23. now we add the um sorry ip address we're going to add in the network so we're going to advertise into ergrp so first is 0 0 0 0 and again the wild mask being that and we don't put in area here because it's ergrp it's using this autonomous system number so that's all you need now we also want to advertise our loopback and all zeros and then that's basically all we need hopefully let's see how we go so i'm going to console into r3 yep r3 is that going to stop flashing spam enter right click and let's see how we go loopback zeros up and zero one is up excellent now we're not going to have any neighbor adjacencies yet because we haven't configured this part or eigrp on router 2. so now we need to go back to router 2 and make those changes so i'm just going to do this in the text editor still back to router 2 but we need to now include a process for ergrp using the same autonomous system 23 and now i'm going to define the networks we're advertising so 10.0.0.0.0 and 0.00.25 now i could just grab that from down below because it should match exactly the same excellent and we're also going to advertise a different loopback that we have not yet created on router 2 and this one's going to be loopback1 at the ip address will be 222.1 and all zeros now don't worry even though we haven't created it yet it's still working this all still works so now i can actually create it i can go interface loopback 1 because we've already got the back 0 and then i'm going to not network sorry i'm going to do ip address and specify the ip address of 2.2.2.1 and all 255's this is subnet mask not wildcard mask okay um and that's not all because we're now advertising this network we're not actually using it anywhere yet we need to add that in which is interface e01 this interface here and do the same thing just give it an ip address 100.2 because we're on router 2 it's a slash 24 and we're going to enable that interface and that should be it now i can either just copy the things i've changed or the whole thing it doesn't doesn't matter if you paste in commands you've already entered it's not going to cause any issues only if you have new commands that change or alter previous ones so if i go back into r2 i've copied from the enable state so i'm going to go back to here to make sure that my commands work and right click and it's going to go through everything again and now hopefully there we are we've got a neighbor change message um notification message eigrp neighbor 1003 being router 3 is up okay now we're not done yet because we still have this connection down here so going back into our text editor i'm going to copy i'll actually copy from this copy and paste and we're going to do r4 move that across a little bit more so r4 no ip domain lookup and on this one we're using interface 0 2 and this is a static route that we're static routes that we're configuring here so i'm just going to put in 192.168.0.4 for router 4 on that network there still 24 so we leave that and it's going to have 4.4.4.4 and that should be it but we want to advertise our routes not through a routing process but actual static routes so we do that by specifying iprout and then the network that we want to advertise right or we want to have a route to so let's firstly do the network that we're directly connected on 168.0.0 and because this is a static route we don't use wildcard masks we actually use the subnet mask and now we need to specify where and either next hop is or our exit interface is so i'm going to use next hop being this interface over here which is not yet configured but that's okay this will still work just won't be routable yet and i'll just expand this out so i can see it a bit better so 102.168.0.2 is what that interface will be on router 2. okay so i've got that route now i also want to add in a static route to another thing that we're going to have for router 2 so i want to have a static route to 2.2.2 dot i could do two or one or both i'm just going to do one all right and that's using that same next hop and that's it that's it for router 4. so we copy this go to the console spam enter right click make sure that's in oh sorry i have made a mistake here let me just go back to the config i uh i put in a slash 24 address for that which is incorrect it needs to be a slash 32 so let's paste that one in it told me uh where was that was wrong inconsistent address and mask so that's how i knew so i've pasted that in and now it should be all good now i also have to make the changes on r2 as well again so we're going back to the r2 config so i'll scroll up a little bit here and let's first add the interface so e02 give it an ip address of 102.168.0.2 it slash24 so i'll do this and then uh no shut we want to turn it on sorry brief value of my brain and now actually i might just exit out of that and then i want to do an ip route for 192.168.0.0 and this is a 24. and this we're doing static route um here so that's why we're using a subnet mask and the next top will be 102.168.0.4 being router4's interface next hop we also want to be able to reach something that is not directly connected but is on r4 and that is 4.4.4.4 and again we want to make sure we remember this time to change this and that should be it for connectivity between r2 and r4 i just add that little bit into r2 oops i have now got two consoles into r2 so i'll close one go back to this i'll exit out of this and just paste straight into there so all i've done is configured e02 turned it on with an ip and added these two static routes actually just press enter there to make sure i get that and that is it for the configuration of the devices so hopefully you've managed to follow along fairly well so far and now we can move into the troubleshooting for the administrative distances okay so for those that have skipped the configuration of the devices welcome and for those that followed along then you should be completely up to date with what's going on but just a quick revision for those that are quick update for those that weren't here we have just configured ospf between these devices eogrp here and static routing here each device has loopback interfaces each one actually has one loopback except for router 2 which has two loopbacks so if i just dive straight into the configuration of router 2 let's have a look at what we've got going on here and i'll just expand this out a little bit and let's do a show ip interface brief so we can see on this device i'll span that out we've got zero zero zero one and zero two all with different ip addresses all up and two loopback interfaces that are up as well so these zero one and two interfaces go zero one and two respectively to the other devices now let's have a look at our routing table this is what we're concerned with as we're delving into the troubleshooting of admin distances so this is the routing table on r2 it's got quite a few different routes that it knows about and let's have a look at the different types so we've got o here if we scroll up a little bit we see that the o is an rspf route we've got connected routes we've got eigrp routes and we've got static that's static route and then we've also got these locals okay so hopefully you already have an understanding of what the different types of these routes are on the different protocols and now for some of these we look on the right we see the admin distance and metric so you should immediately be able to see admin distance of 110 and think oh that's probably ospf because you know that 110 is the default admin distance for ospf routes and conversely we have 90 here you should without even looking here just know that that's probably eigrp internal one static route anything that's not listed you just know that's probably got an admin distance of zero that's why it's not shown and that's what comes up for connected routes okay so now that we've got that solid foundation of what we're looking at here let's figure out what we can do to try and test and troubleshoot when it comes to admin distances so i'm not going through all of the different routing protocols here in this lab but i am just using static routes er grp and ospf as they're the most common ones and they'll also arguably bgp but that's not part of this lab so looking at what we've got here we're going to hypothetically i'll just pretend that we have an internet connection out via r3 this way and via r1 this way so on r2 what we're going to do is specify some default static routes which we don't have at the moment no gateway of last resort set no default static routes so i'm going to do this in my text editor so here i have router 2's config and scroll down to the bottom where we finished configuring the devices and i'm just going to add in an ip route this is specifying a static route to zero zero zero sorry dot zero and that's a subnet mask so all addresses i'm gonna say go via the next hop of this so that would be 10.0.0. or so 1000 and then dot 3 for router 3 as the next hop i'm going to put in another default static route to this way which would be this network so 172.20 sorry 20.0.1 for router 1. so let's just have a look at what happens when we paste this in i'm going to put this in configure terminal enter now we're not going to get any connection messages here and now if i do a show ip route we should see something different up the top here we now see this s with an asterisk so it goes a static route to basically all addresses zero zero zero zero it has an admin distance of one indicating static route via this and via this to the same address so we actually have two routes to the same network available in our routing table so our router can send traffic destined to this address to either of these next hops all right and now we see we also have a gateway of last resort set as well so traffic can be sent to either of these they're both in the routing table because they're both equal they're both they're both of the same prefix length they both have the same admin distance same metric right they're the same type we've got two of them in there okay let's say that i don't want them both to be equal i want to prefer one over the other let's say that i want all my traffic to actually go this way and then we'll just have this one set up as like a backup kind of sitting there all right how do we do that can we do it yes we can so we want 1003 to be the preferred one what we're going to do is actually edit the administrative distance of the other one and make it larger because it's already one the both is already one i'm going to increase the other one that we don't want to use so at the end of this statement you add in a number for the admin distance i'm going to put in 10. so is 10 bigger than 1 yes so this should change what we're actually going to see in the router 2's routing table so go configure terminal paste this in and now i'm just putting 10 on the end i'll just do backslash back slash and then question mark just to show you exactly what we're putting in here if you put in a number at the end it's putting in a distance metric for this route which is exactly what we want to do i'm putting in 10 as a distance metric and now if i get out of this and do show ip route we can see that we no longer have two routes here we've only got the one and that's because the router is only using the preferred route to a given network in the routing table so we still have them both configured which i can verify with show run or just show the running config section ip route and we can see that i've still got them both in here but this one's got a 10 on the end all right so they're still on the device but in the routing table we're only seeing this one now because it's got this lower admin distance all right so i'm just going to now remove that just to turn it back to the way it was so that they're both still in the routing table cool so now we understand what's going on there let's just go back and double check and confirm that the ip routes are both back in there yep so now we have them both back in because i just didn't know at the start of i didn't do no sorry i removed the number on the end and re-entered it back in so now they both have the same admin distance okay so let's say that we actually want all traffic to only go via 1003 so we want all traffic to go this way let's see where it's going to currently go for something that's not in the table so if i just ping 5.5.5 5.5.5.5 because we don't have a route to that and that doesn't actually exist in our lab let's see what happens it fails now what if we trace 5.5.5.5 well when we trace this it's going via 1003. so it's trying to go this way it's sending it to r3 and r3 goes i don't know where 5.5.5.5 is and drops it right it can't it can't send it anywhere but let's say we actually want it to go this way we want all of the stuff that we don't know about to go this way instead what would we do well we'd change the um the metrics right and make it so that all the routes we don't know about go in the other direction yeah cool so we can establish that if it's not in here then that's when we use the the default static routes but because i don't actually have an internet connection it's not going beyond these devices it's just stopping these devices because they don't have routes for them okay now let's say that for example um i'll remove one of these routes so that we're only working with one so it's less confusing so i'll remove okay so welcome to the lab environment as you can potentially tell i'm using gns3 for my labing environments you can use whatever you like but i highly recommend using something that emulates cisco ios versus something that simulates cisco ios so packet tracer for example is a simulator and so because it simulates it can actually behave differently to how cisco ios will actually behave gns3 allows you to use emulation of cisco ios so it behaves exactly as cisco ios does so that's the reason i'm using gns3 but you can use whatever you like all right so just to give you an overview of what we're going to go through is i'm going to actually go through the full configuration from scratch so if you want to skip that timestamp on screen now to allow you to skip forward to when we start troubleshooting the admin distances but for those that want to see the full configuration stay tuned because we're going to get started right now okay so let's just drag in a few routers and that's all we're going to be using in here are some routers for this lab i'm going to use four routers in total so i'm going to drag these across here and it's going to rename them to something a little bit more meaningful to us because at the moment don't really like the names that they're given so r3 and r4 down here excellent and then i'm just going to add a link between each one so i'm going to go from zero zero zero zero zero one to zero one and finally zero two to zero two noting here i've got ethernet as my interface name so i specify these with e 0 0 they're all connected so i click start if you're following along in gns3 and now i'm going to start writing out my configs now i'm actually going to use a text editor to write out my configs just to make it easier to copy across between devices so we'll start with enable and configure terminal and then i'm going to specify my hostname so for r1 is what we're going to be working on first and then no ip domain lookup just so that if we have any typos you have to wait for that and now let's get cracking straight into the interface so e0 is what i'm configuring here on r1 and just going to go to set the ip address now for this r1 to r2 connection we're using ospf and this is the network statement here so for each device the final octet is just going to match the number of the router so this interface here is 172.201 so 172.20.0.1 and of course put in the subnet mask being a slash 24 subnet mask we're then going to enable that interface oops and that's it for that interface now each into each router is also going to have at least one loopback interface so loop back 0 or if you want to make writer even shorter lo0 that's loopback 0. give this an ip address of 101.1.1 and it's going to use all of the bits in the subnet mask no shot and then we can move on to the lsbf definition so ospf process so i'm going to use process number one and now we need to advertise our network so i'm going to advertise the 172.20.0.0 network and then the wildcard mask so because of slash 24 and now we put in the area statement at the end don't forget that crucial part now that's not all we also have another network statement that we need to put in here because we're using that loopback we want to advertise that through to our neighbor or ospf neighbors if we had plural and obviously that's how the wildcard mask is going to be set and same thing area 0. and that's actually it that's it for router one for now at least so just configuring the basic things you can either double click or right click and click console to bring up the console session and i press enter a few times just to clear the screen a little bit and then right click to paste in so it's pasted in all of the things that i entered before and we can see here let me just expand this out a little bit it has changed loopback 0 is up ethernet 0 0 is up and that's basically it that's all we expect so far so let's move on to router 2. so i'm just going to keep this copy and paste and just change it for router 2. so hostname is r2 and same interface e0 but this is going to change to dot 2. loopback 0 zero that's fine we'll keep it a zero zero but we'll obviously change this to a different number so two two two two for router two process id can stay the same for ospf network statement can stay the same for this network but we want to advertise our loopback interface not router one's loopback interface and that's it done so that's why we're using a text editor makes things a hell of a lot faster now if i go into r2 spam that a few times right click it's pasted everything in now hopefully we'll see something a little bit different this time sorry i had to press enter and loop x0 is up ethernet 0 0 is up and now we can see this ospf message so it's a notification message level 5 process 1 on this neighbor so this is the ospf id which r1 has taken from the loopback interface address so if you don't specify that's where it gets it from and it's gone from loading to full excellent so now we've got an ospf neighbor adjacency awesome now let's continue on with the configuration so let's go to r3 so i'm going to move this across to this side now just so we can see what we're working with on the other side i'm still going to copy this and paste it in here but it's going to change a few more things this time so i'm going to change that to r3 and you also might have noticed that these already had the correct name so as soon as i press enter it already had r2 and the reason it really had that name is because i changed the name here before i turned these devices on and so that's the name that it takes when it starts just if you're wondering so back to r3's configuration we're no longer using this interface we're using 0 1 because this is 0 1 and this is 0 1. and this iop address is now completely incorrect we're using eigrp and this network on this side so for r3 it's going to be 100.3 still a slash 24 though now we're going to change this just to all threes and this can now be completely deleted so we're not using router ospf we are using router ergrp and we'll just use the classic ergarp so we're going to specify the autonomous system number 23. now we add the sorry ip address we're going to add in the networks that we're going to advertise into ergrp so first is 000 and again the wildcard mask being that and we don't put in area here because it's ergrp it's using this autonomous system number so that's all you need now we also want to advertise our loopback and all zeros and then that's basically all we need hopefully let's see how we go so i'm going to console into r3 yep r3 is that going to stop flashing spam enter right click and let's see how we go loopback zeros up and zero one is up excellent now we're not going to have any neighbor adjacencies yet because we haven't configured this part or eigrp on router two so now we need to go back to router 2 and make those changes so i'm just going to do this in the text editor still back to router 2 but we need to now include a process for ergrp using the same autonomous system 23 and now i'm going to define the networks we're advertising so 10.0.0.0.0 and 0.00.255. now i could just grab that from down below because it should match exactly the same excellent and we're also going to advertise a different loopback that we have not yet created on router 2. and this one's going to be loopback1 at the ip address will be 222. and all zeros now don't worry even though we haven't created it yet it's still work this all still works so now i can actually create it i can go interface loopback 1 because we've already got the back 0 and then i'm going to not network sorry i'm going to do ip address and specify the ip address of 2 2.1 and all 255's this is subnet mask not wildcard mask okay and that's not all because we're now advertising this network we're not actually using it anywhere yet we need to add that in which is interface e01 this interface here and do the same thing just give it an ifp address 100.2 because we're on router 2 it's a slash 24 and we're going to enable that interface and that should be it now i can either just copy the things i've changed or the whole thing it doesn't doesn't matter if you paste in commands you've already entered it's not going to cause any issues only if you have new commands that change or alter previous ones so if i go back into r2 i've copied from the enable state so i'm going to go back to here to make sure that my commands work and right click and it's going to go through everything again and now hopefully there we are we've got a neighbor change message notification message eigrp neighbor 1003 being router 3 is up okay now we're not done yet because we still have this connection down here so going back into our text editor i'm going to copy i'll actually copy from this copy and paste and we're going to do r4 move that across a little bit more so r4 no ip domain lookup and on this one we'll be using interface 0 2 and this is a static route that we're static routes that we're configuring here so i'm just going to put in 102.16 for router 4 on that network there still 24 so we leave that and it's going to have 4-4-4

Channel: Your IT Explained

Views: 40

Keywords: Ccnp, enarsi, cisco, exam, topics, troubleshoot, tshoot, aus, aussie, admin dist, 1.1, lab

Id: PHzyDCcFRfI

Length: 37min 8sec (2228 seconds)

Published: Mon Sep 27 2021