Original subtitles

Okay for this question and on a blog I got a question from Remus.

He asks What is the use of giving a default gateway to a switch using the IP default gateway command

be remiss in this June 3 typology of a router connected to a layer 3 switch which in turn is connected

to a lead to switch at least three switch has IP routing enabled.

In other words it will rot from Villon one to violent two and back again switch to a late to switch.

In other words it doesn't have IP writing enabled.

So for the CCMA this could be a twenty nine fifty switch or 21:16 and this could be a 37 50 35 50 as

an example.

So on Router one is Rotto 1 able to ping switch to on trees.

No the router is not able to ping switch to.

What about trace and to speed things up I'm going to.

No IP domain.

Look-Up so trace route to tend and wondered wondered what.

OK so the traffic gets to switch one so it goes from about a one to switch one tenth of 1 to 2 to 2

5 4.

And then the trace fails so cannot ping 10 1 2 5 4.

Yes I can and I would have known that from the trace.

But what I'd like to do is check the following.

Can write a one paying the same IP address on the other side.

Well switch one.

Yes it can.

So that means that the problem is not here.

The problem is somewhere on the site so on switch one can we paying switch to.

The answer is yes.

On switch to Kennet paying switch one on villaine one.

Yes it can.

But Kennet paying a cross switch one remember one was able to ping this IP address in Villon one so

switch one is going to be LAN routing but can switch to pings which ones IP address in violent too.

And it looks like it can't this is a very typical Signoria way.

You can't ping or telnet to a switch in a remote subnet.

Now on the switch when we use the command show IP raht notice no default gateways being set.

This means that IP writing has been disabled on the switch.

So what I need to do is type IP default gateway and point the switch to its default gateway so show

IP.

Notice default gateway set told you that come on again is the default gateway.

So on router 1 10 we paying switch to monsters yes.

So you need to configure a default gateway on a late to switch.

In other words a switch that hasn't got IP routing enabled to allow that switch to send traffic to remote

subnets traffic from router one could get to switch to but won't be able to get back again if switch

to doesn't have a default gateway configure it.

Now this can get confusing if the switches the last three switch or supports Les's free functionality.

Notice at the moment once again IP routing is disabled because we don't see a writing table here show

run pipe include IP raat.

Notice this command.

No IP routing IP writing was disabled on the switch.

That's a default on all the switches.

So IP routing that's enabled that through the show IP wrapped.

Come on again notice the output is very different.

Notice also that the gateway of last resort is not set.

So Ken wrote a one ping switch to answer his node show run pipe include default.

We still have the IP default gateway command configured on the switch but because IP routing is enabled

that command is ignored.

So you only use the IP default gateway command when IP rodding is disabled so let's do that again.

No IP routing

pings succeeds IP routing

Pingo file.

So an IP routing is enabled like this.

What you need to do is you need to create a default route to a default gateway so something like that

and now routing works.

So here's the thing to remember if IP routing is enabled on a switch you must use a static default drop

like this will run a routing protocol if IP routing is disabled.

He used the IP default gateway command to allow a switch to send traffic to a remote subnet remiss.

I'm hoping that answers your question and I hope that helps everyone else.

Don't forget to ask questions in the comments below.

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I want to wish you all the very best.