I'm new here and also with networking but i can't set internet conection for some vlan created.

I have a Cisco CE500 switch and created 4 vlans define by the roles in the switch. Vlan 2: Servers (role) (port 3-4) Vlan 3: Desktop (role) (port 5-8) Vlan 4: Guest (role) (port 9-12)

Vlan 1 is default, Connect to the ADSL Modem/Router Port 2 assign to the Router Role (vlan 1)

The switch is connected on port2 the ADSL Modem (DHCP) The goal is: All Vlan should have internet connection. Vlan 2 and 3 should see each other but not Vlan 4

I can enter the switch CLI but dont know which command to enter.

Thanks 4 ur time and replies Jennifer

  • 1
    What is providing L3 connectivity between the VLAN's? Does the ADSL modem have routes back to the various subnets or is it directly connected via a trunk? If the above questions don't make sense then you might have better luck over at superuser.com. – rnxrx Nov 11 '12 at 22:31
  • Most likely the modem is unaware that you have multiple subnets on your Cisco switch. If you can add static routes into the modem, then you can resolve your issue by telling it the new subnets are behind the IP of your switch. – SpacemanSpiff Nov 11 '12 at 23:48

I doubt very much that the DSL modem is able to do what you'd like it to do. In your scenario you would typically:

  1. Configure the switch port that connects to the router as a trunk port. This allows the switch port to carry traffic for all VLAN's.

  2. Create subinterfaces on the router interface that connects to the switch and configure those subinterfaces with an ip address appropriate to each VLAN subnet. This allows the router to route traffic between all the VLAN's.

This is generally referred to as a "router on a stick". Here's one example using Cisco equipment:


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  • Standard business class DSL modems can CERTAINLY do inter-vlan routing. I have a stack of Netopia DSL gateways here that even have stateful firewalling, destination/source NAT, and QoS. – SpacemanSpiff Nov 11 '12 at 23:46
  • Sorry 4 my late response. Thanks 4 the replies. @Joe , I will try that – Jennifer Nov 14 '12 at 21:23

As joeqwrty said comes from that inter vlan communications can be only achieved on layer 3, meaning that you either need Layer 3 switch or external router, which again I doubt that any DSL modem carries that functionality. Hope this helps.

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