VLAN security

DevilWAH

How secure are VLAN's?

does any one have some documentation on this.

basicaly I want to tunnel a unsecure / unmanaged broadband connection across the site VLAN.

so

ADSL router ---- Cisco 3750 ---- lots of other stuff ---- Cisco3750 --- PC

my idea is set the ports on the 3750's to access ports and vlan 50, (which is not native).

Prune of vlan 25 from any switchs it does not need to pass through.

My company want to spend out money getting a entire seperate fibre/hardware installed to carry this across site.

What methiods are there for some one on the PC or the ADSL router for compermising the security of the comapny network.

of course there would be access lists on the 3750's to restrict the traffic to a set ip subnet and no layer three routing for that network be the company network.

I don't see the point in spending out £1000's and possible having it refuesed when we already have the kit to do it securaly in place. Or is there some thing I am missing.