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I need to configure two vlan on an AP connected with a Dell PowerConnect 2848. The first one is up and running (let's say vlan x) , the second one is a completely different network (vlan y) , provided by a Gateway-DHCP wich i have no access, directely Patched (via patch panel) at a secondo AP device.

So i cannot just plug this Gateway device on my switch without tagging traffic before, for DHCP collion . I have to solve this problem. I was thinking about tagging the traffic at the port wich I will connect the gateway device with vlan y and then set as trunk (vlanx+y) the AP port. In this way I hope to limit the vlan y traffic ONLY for the ports I selected avoiding the spread of unwanted dhcp calls. But all other ports are Unassigned , so I am not sure they won't forward dhcp (vlan y) traffic.

I cannot change the Unassigned state for the vlan x ports cause vlanx is native.

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DHCP server is on VLAN y, yes? – gravyface Oct 2 '12 at 10:47
There are 2 dhcp, 1 for net. My problem is in fact to avoid a DHCP collision – Francesco Oct 2 '12 at 10:54
up vote 0 down vote accepted

I'm not 100% sure I understand the question, but it sounds like you have an existing DHCP server/network setup on the native VLAN ("x") on the PowerConnect and you'd like to create another VLAN ("y") for strictly wireless use; on VLAN "y" I'm assuming you have a router that's running a DHCP server for your wireless clients and will also be the wireless client's gateway.

I'm not going to get into syntax/UI commands, but typically there will be a SSID-to-VLAN mapping where you'll want to assign a VLAN ("y") to the SSID in the AP's management user interface (UI). This will tag VLAN "y" traffic that leaves the uplink (or "LAN" port) on your AP for any wireless station (client) traffic associated with that SSID.

Usually you can also tag the non-wireless traffic (for instance, access to the Web/SSH/telnet management UI of the AP) if you'd like, or leave it untagged, which will put the AP's management interface onto the default/member VLAN that the port belongs to on the switch.

For the switch, you'll want to enable tagging for VLAN "y" for the port where your AP will be plugged into.

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So if I plug the DHCP/Gateway for vlan y on a Port tagged Y all the traffic will be allowed just for the AP port (x/y) or will be forwarded on every unassigned port? – Francesco Oct 2 '12 at 12:04
the AP is already correctely configured with SSID-to-VLAN with proper Vlan ID. – Francesco Oct 2 '12 at 12:04
I m mostly scared of a secondo dhcp (with a completely different addressing pool) answering dhcp requests on the first vlan (x) – Francesco Oct 2 '12 at 12:06
and, for istance, If'd like to plug a notebook on a Tagged port in vlan Y It shouldn't be able to ping or access a machine in vlan x without a router , right? – Francesco Oct 2 '12 at 12:41

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