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This is one of multiple videos discussing static routing.

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I've received a number of questions along the lines of multiple default routes supported on a router. In

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this apology we have four routers and we are concentrating on router 1 which has three paths to get

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to the loopback of router 5. To get to 5.5.5.5 router

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1 can go via router 2 or via router 3 or via router 4.

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So have a look at this routing table and tell me which way will router 1 send traffic to the loopback

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of router 5?

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So let's do a trace.

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What you'll notice is that the pings fail and they fail because the gateway of last resort is not configured

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and there's no specific route to 5.5.5.5.

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If we use the command debug IP packet we'll be able to see what happens when router 1 pings router 5.

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I'll send a single ping in this example.

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And what you'll notice is we're told that the packet is unroutable.

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The router doesn't know where to forward the packet

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so it simply drops it.

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If we want to send traffic to router 5 we need to configure a static route or configure a routing protocol.

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So this option ABCD forwarding routers IP address allows us to specify the next-hop IP address and we

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interface or to the next hop IP address.

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So this option ABCD forwarding routers IP address allows us to specify the next-hop IP address and we

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can also specify a administrative distance for the route.

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I'm not going to do that here.

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I'm going to press a carriage return.

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What this has done is set a default route to router 2.

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So show IP route now shows that we have a gateway of last resort configured of 10.1.1.1.2

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to the default network we can see a static ROFFT So notice the stall asterisk denoting candidate to

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default route. The router has a default route via 10.1.1.2 notice the administrative

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distance of the routers one the administrative distance or believability of a static route to a next

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hop IP address is one.

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So that's a lot lower than a routing protocol such as OSPF or RIP, RIP as an example has an admin distance

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of 120 if you can figure out a static route to the local outgoing interface it would have and it must

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administrative distance of zero.

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So now when we ping quadruple five the ping works I'll turn off that debug and do that again.

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So Ping succeeds and if we trace to the loopback it's going via router 2 10.1.1.2 and that's because

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once again the default route is pointing to router 2.

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So can we configure another default route.

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So as an example, can we configure it to go via router 3, 10.1.2.2?

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And the answer is, yes we can.

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If we configure it to default the gateways

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notice how it shows in the routing table we can ping router 5

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and when we trace to router 5 the router is gonna load balance across those two paths.

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So it's gonna load balance with one packet going to 10.1.2.2 and one packet going to 10.1.1.2 and 

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we can see that in this output here.

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Notice the traces are load-balanced across router2 and router 3

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and then we see router 5 as the next-hop depending on which path that traffic took.

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So it either goes via this top link or the second link.

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So show IP route shows us that again we could add a third route via router 4. So show IP route notice

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we have three entries in the routing table and if we trace to 5.5.5.5 traffic is load-balanced across

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those three static routes.

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So in answer to the question, can you have multiple default routes?

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The answer is, yes you can.

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The router will load balance across those parts equally.

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Now you can change the administrative distance.

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So at the moment if I type do show run pipe include route will see the three static routes in the running

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config of the router and what we could do as an example is remove the routes from the routing table

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and add them back with different admin distances.

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So previously the administrative distance was one but we cannot change that. Before we change it

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notice do show IP route shows us that we no longer have any routes to router 5.

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And if we ping that back to loopback the pings are failing because there's no route in the rotting

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table.

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I hope you enjoyed this video, if it was of benefit to you please like it and please subscribe to my YouTube channel.

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I wish you all the very best.