VLAN Trunking allowed vlan issue

GooberTech asked this question on 12/8/2011. It has been viewed 639 times, and is currently unresolved.

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I am having an issue with Cisco switches & trunking.

I have set up a small network in packet tracer.

I have various vlans connected to an access layer switch.
This switch is connected to a layer 3 switch.
I can route traffic to all of the vlans no problem including the server.

My issue is that all VLAN can connect to the server, even though i have only allowed some of them.

Any ideas why this would happen?


Answer from alexkw on 1/21/2013

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Dear GooberTech,
Buddy, I presume that you have put everything in the same SUB-NET.

So, here's the problem !

Devices in same subnet can PING each other . . .

You, my friend, need to put a routing config. between VLANs. U may use the 'Router on a stick' configuration.

Send me the Topology file exported from Cisco Packet Tracer. May be I can get it straightend out for you.

Alex W.


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