CCENT4

Static Routes (Recursive and Directly Connected)

As we were suspecting, R2 cannot ping R4. They are on different subnets and version 6 is advanced but not that advanced! So we have to add a little something here…

Typically in a network we could and likely would configure OSPF, RIP, or EIGRP for IPv6, but we’re saving those for another IPv6 section.  That leaves only one solution – static routes!

We have static routes, host static routes, default static routes…

But first we’ve got to cover these regular ones and by regular I just mean that they are not host routes which match only one address, and they’re not default routes. They’re just regular static routes!

We can use one of three types of “regular” static routes:

Recursive, where only the next-hop address is specifies.

Directly Connected, where only the output interface is specified.

Fully Specified, where as you’d expect from the name, both the next-hop address and output interfaces are specified.

We’ll use a  recursive route on R2 to allow it to communicate with R4. The ipv6 route command follows the same syntax as ip route, where you put the destination network first and the next-hop address last.

So what does that mean?

That means that we’re not configuring this on the interface. So there is an IP V6 route command for the interface. Don’t use it!!  (IS-IS is not part of CCNA studies)

I showed you that because while I wanted to show you there is an IPV6 route command for the interface level but that’s not what we’re using here.

We’re using IPv6 route in global configuration mode.

Don’t worry about “static” and “vrf” for now…  We’re going with the “prefix” and this is the prefix for the destination. (Just like with the IP route command where you put the destination network first, this is always going to be the destination)

right now we’re much more interested in that next to last option which is “IPV 6 address of next-hop”. (we’ll talk about the rest later)

Now which address on R3 is that going to be? that’s going to be the one we pinged earlier

That’s going to be 2001:2222:3333:1::3 … That’s going to be the next hop IP address.

We’re almost there (actually for this one we are there).

This again is a recursive static routes…

Now when you were looking at this table earlier even though I said the only three were the ones at the very first (connected, local and static) I’m sure you want to look through the rest of this and you might have noticed that the asterisk(*) for candidate default is missing. It’s not there and you’re just going to see an S here(white area) even when this is a static default routes… something you got to get used to.

But there’s our first static route. It looks awfully good. We see the prefix we’re going to, the network we’re going to, and the next stop IP address…

L et’s go ahead and try pinging R4

We’re getting timeouts which is not good.

What’s the next thing you’d likely do?

You’re trying to ping a destination that you expect to be able to ping and you can’t do it.

What’s probably the next thing you should do? ping an address that’s close to you! Start coming back and see where the trouble is…

And what I would do here is pinging R3’s Fast Ethernet interface.

that ping goes right through as we would expect … It went through before.

So that’s no problem.

The issue here is that the packets when they get to R4, they don’t know how to get back.

So to have end to end communication with static routing, not only does R2 have to have a route pointing to R4, but R4 got to have a route pointing to R2.

So let’s go over to R4, and we will put in a directly connected static route, which uses only the output interface.

and this time we’re going to use the interface option

and there are the remaining choices none of which we want to use

So that’s all there is to a directly connected static route…

and let’s go ahead and send our ping

and successful… R4 can ping R2 … now we’ll send one from R2 to R4

And now it goes through…  So that’s all about recursive static routes.

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