CCNP: multi layer switching

Node Man

Hi Everyone,
I hope you are having a nice day. I think I need troubleshooting guidance or I am missing a piece of the puzzle.

I am trying to set up a 3550 switch in my lab. My home Internet is a 192. net and connects to fa0/1. My desktop computer is a 172. net and attached to fa0/2. My desktop can ping the 3550s 192, but it can't ping my houses 192 gateway. This is something I fought with for while. Must the interfaces have ip's or are the vlan ip's enough?


Any guidance is appreciated.

Thanks!

stlsmoore

Was the 3550 192. ip address configured on an SVI port or on fa0/1? Also does your home gateway know how to reach that 172. subnet you created with a static/dynamic route?

Node Man

192 is svi, vlan 1. The linksys has not been touched in any way. The 355

Node Man

192 is svi, vlan 1. The linksys has not been touched in any way. The 3550 can ping everything including 8.8.8.8

theodoxa

The 3550 would be able to PING anything because it is directly connected to both the 172 and 192 subnets. If you PING from the 3550, it will source it from the interface connected to that subnet. I would assume that the Linksys has no route back to the 172 network and more than likely given what I've seen with Home Routers (most either don't support static or dynamic routing at all beyond the connected and default routes or if they do support static routing, only support it on the WAN interface to support a second internet connection), probably has no way of configuring a route either.

Try --

ping 8.8.8.8 source Fa0/2

tomtom1

theodoxa wrote: »

The 3550 would be able to PING anything because it is directly connected to both the 172 and 192 subnets. If you PING from the 3550, it will source it from the interface connected to that subnet. I would assume that the Linksys has no route back to the 172 network and more than likely given what I've seen with Home Routers (most either don't support static or dynamic routing at all beyond the connected and default routes or if they do support static routing, only support it on the WAN interface to support a second internet connection), probably has no way of configuring a route either.

Try --

ping 8.8.8.8 source Fa0/2

I don't think fa0/2 is a routed interface but I get your drift. When testing connectivity, also check the return traffic and I guess this is the issue here, as also mentioned by the other ones in this topic.

Node Man

I thought the 3550 would do the job of routing the 172 net to 192. Why does the linksys need to know anything about the 172 net?

Node Man

Maybe a better question would be "how to I connect my lab to the outside world?"

Hondabuff

Read, Learn, Do! I think you still need a static route on the Linksys to tell it where your 172 network is.
How To Configure InterVLAN Routing on Layer 3 Switches - Cisco

xnx

As above, should be a simple task as my CCNP lab connects into my home network (2 separate networks).

Danielh22185

Node Man wrote: »

I thought the 3550 would do the job of routing the 172 net to 192. Why does the linksys need to know anything about the 172 net?

It needs to know how to get back to where you are pinging from (this is Routing 101). Essentially what you are doing is sending a request to the home router to respond. If it does not know how to send it back then this is where your failure will occur. A good way to troubleshoot this is trace it too. Where does the trace end? If the home router does not know how to route traffic back then I would image you will find the trace to end 1 hop before it reaches your home router (i.e. your 3550 switch).

xnx

Yeah, remember that your home router will need a static route back to your cisco router / MLS

Ryuksapple84

What internal IP is your home router setup for? Usually it should just plug in and work but in this case you may need to tell the home router of the other network.