Cisco 3750 Routing the interfaces on the same subnet

Unanswered Question
Mar 14th, 2007
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Hello all,

Question is it possible for a Cisco 3570 to have two vlans with the same subnet and route in between them?



current topology

A flat LAN with a default gateway of This gateway device is a firewall out to the internet.


Addition of WAN line.

A WAN line via a 2811 router is now connected to the switch. which provides access to the network.


So I could I configure routing between three vlans with two of them being the same subnet

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ankbhasi Wed, 03/14/2007 - 11:08
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  • Cisco Employee,

Hi Brian,

It is not possible to have 2 different vlans with same subnet. If you try to assign the same you will be prompted with an error message saying "overlapping address".

On the reverse side you can have same vlan with different subnets using "secondary" keyword.




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