vlan interfaces on multiple L3 switches?

[hmc250000]

I've seen someone configure 1 vlan interface on multiple switches ( 2 x MS250s and 1 x MS120) with the same ip address on each of the switches in a site. The 3 switches are stand alone switches and not stacked.

IS this a supported configuration? 

[alemabrahao]

Definitely not. Don't do it.

[hmc250000]

Can you elaborate what issues to look for specifically? It was already implemented by this person and it seems like it's functioning like normal. I see no errors on the switches and it's not even complaining about ip conflicts.

[alemabrahao]

The most common is IP conflict, this is not a common thing to have on a network. If you want to keep it that way, that's ok, but it's at your own risk.

[DarrenOC]

The Ms120’s are Layer 2 only so I’m assuming that the vlan in use is also your management VLAN?

If that’s the case I’m surprised the devices have managed to register out to the cloud without issue.

[hmc250000]

My mistake, you are correct the MS120 is L2 only but has the interface added for DHCP relay. The other 2 MS250s do have the vlan interface added for routing.

And yes, all ports are in vlan 1.

And I do see a lot of status change spanning tree port activity.

[Brash]

Assuming the dashboard lets you configure it (I've never tried), it's not a good idea.

There's no reason I can think of that you would purposely want to introduce duplicate IP addresses into your environment - It's just asking for trouble.