AWS Essentials: Route Tables (RTs)

hello and in this lesson we are going to continue building on VPC basics this time talking specifically about Route tables and touching on Route table definitions the function of a Route table creating and deleting a route table and setting routes in the route table so to start off let's talk specifically about some route table definitions so the simplified definition is well the AWS definition is simple enough so let's just jump right down to it a route table contains a set of rules called routes that are used to determine where network traffic is directed and we should note here that your default VPC already has a main route table so let's take a look at that right here under route table or you can always click on it here this is our main route table and we know that it's our main route table under the column here it says yes for main now before we dive into the various aspects here on the console let's take a look again conceptually at what the route table does so in our VPC diagram we have our internet we have the internet gateway which we discussed last lesson and that's what provides us with access to the outside world for VPC but then once inside our V PC we need something to tell the data where to go so when information comes in from the internet say a website a computer in the V PC would have requested that information so the information that it's coming back in has a little packet of information with it that says hey this is the computer or this is the server that this information needs to go to and it's the route table that takes that and says ok this is the one that you need to go to or maybe there's one over here that you need to go to but it's the route table that provides the connection between all the various resources within your V PC and back here under the console if we look down here next to summary and we click on routes this is what tells us what's attached to this route table and where things are going to go so the first thing I want you to look at and concentrate on here is this part right here which is igw which if you haven't already guessed stands for the internet gateway so this right here this connection represents this line right here this is the connection or the route between the route table and the internet gateway the other section here this is the IP address or the site or block range of the VPC itself so this here is basically these lines here that provide the route around the internal aspects or the internal parts of the VPC now for demonstration purposes let's have a little bit of fun let's click on our internet gateway here to open up Internet gateways in a new tab and if I clear out the auto sort here we can see our two Internet gateways the one we have attached to bb-8 and the one that I created in the previous lesson so the bb-8 that's the one that we have connected that's the one currently right here in our diagram what would now happen if I were to detach this from the V PC well let's give it a try and see what happens so I detached it from the V PC and basically what's happened now is this I've detached the Internet gateway from the V PC but the route table is still routing to it so let's click back and let's refresh the route table page click on the route table and click on routes and now here under this before where it said active it now says black hole so that just means that the route to the Internet gateway is just going nowhere it's going to a black hole so any information sent through it would just go off into the nether regions so if we were just to simply reattach this particular gateway well we would just go right back to this and everything would work just fine but for this example let's now attach the other gateway that I created to the VPC so now I have another Internet gateway here but we're still routing to the Gateway that has been detached we're still routing to the bb-8 detached Internet gateway so if I now edit this and remove that route and add another route the drop down is now going to give them the option of adding the essentials Internet gateway I can click Save all destinations must be a valid cider box so this I'm just going to put 0 and click Save we now have an active route to the Internet through an active gateway and that brings us right here now to this diagram where this was our default internet gateway that was detached so we detached it we attached a new Internet gateway to the V PC and we switched the route so we took the route that was going to this internet gateway and when we change that here we change the route now to the Internet gateway that's attached to the V PC and we have now restored Internet access to the V PC so I just want to make sure that you have a good understanding of what route tables do and how they work within a V PC now there are a lot of advanced features to a route table but for the purposes of the AWS essentials course I just want you to conceptually understand its purpose and how it routes and connects different elements components of the V PC with each other so again to sum up a route table contains a set of rules called routes that are used to determine where network traffic is directed and unlike an Internet gateway you can have multiple active route tables in a V PC and you cannot delete a route table if it has dependencies associated with it so just to kind of show you what I mean by that let's create a new route table I'll call this Essentials route table wrap table and again we only have one VPC to select from so I'll click create and we now have a route table which is not our main route table and does not have any subnets explicitly associated with that we'll talk more about that when we get to the subnet sections but for our default route table which does have subnets internet gateways and things routed to it if I were to try to delete this right now it would not work comes up and it says you cannot delete the following route table it has dependencies it cannot be deleted but if I were to click on this delete this route table because it has nothing associated with it now it can be deleted so again just want to do to be aware of those two aspects that one you can have multiple route tables in a V PC which we're going to use in a little bit and then also you cannot delete a route table if it has dependencies so with that I thank you for watching we will conclude this video you may now move on

Channel: Linux Academy

Views: 68,340

Keywords: Linux Academy, LinuxAcademy.com, AWS, Amazon Web Services, AWS Essentials, Cloud, Cloud Computing, Beginner, Education, Training, Tutorial, VPC, AWS VPC, Virtual Private Cloud, Route Tables, RT, AWS RT

Id: GrfOsWUVCfg

Length: 7min 52sec (472 seconds)

Published: Wed Dec 21 2016