Layer 3 Switch act as Layer 2 switch

[Caitlyn Sims]

Hi,

I have a question regarding my layer 3 switch. Currently, the network works fine except that the layer 3 switch (which is Curly) cannot ping outside the management VLAN, and other devices cannot ping it. Moe can ping all devices fine.

So, my question is, how do I get Curly to ping the PC's and other router interfaces. I have not had much experience with the 3560 switch. Any help would be greatly appreciated

Thanks 

[Jon Marshall]

Cannot read your attachment but at a guess if the L3 switch is not routing and has just a L3 vlan interface for management then you need to add -

"ip default-gateway x.x.x.x" 

where x.x.x.x is the L3 interface on another of your devices that is responsible for routing the management vlan.

Jon

[Caitlyn Sims]

Hi Jon,

Sorry about the attachment, wouldn't let me upload just the packet tracer file and had to zip it up.

The L3 switch already has a default gateway, that of the IP address of the router sub interface of the management vlan.

VLAN 452 is the management VLAN, and in the picture the default gateway for the switch is the same as the sub interface on the router.

[Jon Marshall]

I actually meant not all of us have access to the software you are using so best to attach configurations and a diagram.

It sounds like it is setup correctly with it's default gateway.

Assuming the L3 switch only has one SVI ("int vlan x") and that is the management vlan and assuming that the trunk connection is allowing the vlan then can you make sure IP routing is not enabled on the switch otherwise it will ignore the default gateway setting.

If that makes no difference attach configurations and diagram.

Jon

[Caitlyn Sims]

Ok, sorry, I'm very new to this forum.

I have attached the device configs for Larry (the router) and Curly (the L3 switch), and also the diagram

[Jon Marshall]

No need to apologise :)

Okay, your configurations look good at the moment.

So from the switch can you ping 83.174.64.206 ?

Can you also post from the switch the following -

"sh int trunk"
"sh ip route"
"sh vlan"

Jon

[Caitlyn Sims]

Yes, the switch can ping 83.174.64.206 and ....204 (which is Moe).

[Jon Marshall]

Again it all looks fine.

Just to clarify do all devices use the router as their default gateway IP in the respective vlans ?

Jon

[Caitlyn Sims]

Yes. While I was testing yesterday I checked and both the pcs can ping each other, and moe can ping every sub interface of the router, but curly can only ping the vlan.

[Jon Marshall]

-

[Caitlyn Sims]

Yes, that's correct. L3 switch cannot ping outside of the management VLAN.

Here is the spanning tree vlan 452

Curly#sh span vla 452

VLAN0452

Spanning tree enabled protocol ieee

Root ID Priority 25028

Address 00E0.F774.E59E

This bridge is the root

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 25028 (priority 24576 sys-id-ext 452)

Address 00E0.F774.E59E

Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Aging Time 20

Interface Role Sts Cost Prio.Nbr Type

---------------- ---- --- --------- -------- --------------------------------

Fa0/11 Desg FWD 19 128.11 P2p

Po1 Desg FWD 9 128.27 Shr

F0/11 is the connection to the router and Po1 is an EtherChannel link to Moe, the L2 switch

[Caitlyn Sims]

And the arp table after trying to ping 83.174.64.190

Curly>sh ip arp

Protocol Address Age (min) Hardware Addr Type Interface

Internet 83.174.64.190 0 0001.6499.8402 ARPA Vlan452

Internet 83.174.64.205 - 00E0.F774.E59E ARPA Vlan452

[Jon Marshall]

You should not see an arp entry for 83.174.64.190 because, unless I have got my maths wrong,  it is in a different IP subnet.

The only arp entries you should see would be for devices in the same vlan/IP subnet as the L3 switch.

It looks like the switch still thinks it should be L3.

This should not make a difference but can you on the switch administratively shutdown all the other vlan interfaces except the management one obviously.

Jon

[Caitlyn Sims]

Hi Jon,

This is what appears as it is freshly opened, with the other vlans shutdown.

Curly>sh ip arp

Protocol Address Age (min) Hardware Addr Type Interface

Internet 83.174.64.205 - 00E0.F774.E59E ARPA Vlan452

And yes, 83.174.64.190 is in a different vlan, the final usable address in the vlan before I believe.

[Jon Marshall]

If you now ping 83.174.64.190 what you should then see in the arp table is an entry for 83.174.64.206 ie. the default gateway for the management vlan.

Can you try that and post results.

Jon