Switching - Vlan question

Unanswered Question
Jan 27th, 2009


I have a Vlan question

If i have a Core switch that is working as a layer 3, and that core switch is attached via trunk to another 2 x Cisco layer 2 switches (as seen in the topology)

My question is if there is a room where all pc's are connected to layer 2 non manageable switch and that switch is connected to the Cisco Layer2 switch, will there be able to get DHCP addresses from the DHCP server(in VLAN 10) if the port where it connect the Unmanageable Layer 2 to the CISCO 1 is configured as VLAN 6 (for examples) and has the ip-helper address command.

I did a topology that explain better my problem, will the Workstation get IP's from the DHCP server?

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Overall Rating: 4 (1 ratings)
Jon Marshall Tue, 01/27/2009 - 13:24


Can't read the .vsd as i don't have visio available. You can post as a .jpg if needed.

But in answer to your question if the pc's are connected to an unmanaged switch and this switch is connected to a port in vlan 6 as long as the vlan 6 L3 interface has the correct address for the DHCP server the clients will get an IP address ie.

int vlan 6

ip helper-address


Mohamed Sobair Tue, 01/27/2009 - 13:44


If you have (Ip helper-address) Configured On the l3 Switch Interface, and routing is enabled between both vlans, then the workstations should be able to get their IP Addresses. The (IP helper-address) enables ur Switch to forward UDP broadcast traffic directly to the accessible DHCP Server.




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