Author Topic: DHCP / VLAN problems since switch upgrades  (Read 1710 times)

Offline cenkozkan

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DHCP / VLAN problems since switch upgrades
« on: November 30, 2022, 09:17:42 AM »
Hi all,
We have recently upgraded all of our switches to Aruba 6100/6200's. All ports are configured as trunk native vlan 1, trunk access allowed all.  Vlan1 is data/default. Vlan2 is voice.

Since the upgrade we are having problems with PC's that are attached to Mitel 6930 phones (LAN ports). Essentially the phones work perfectly and get an IP address on the phone network, which is 3.x but the PC's randomly get IP's from Phone and Data which is 1.x. 

Essentially two DHCP servers fighting. Data network has DHCP server on Windows, Mitel phones get it from Phone System.

My question is what's different on these switches that we are missing, the previous HP switches were configured in exactly the same way.

Things I read point me in the direction of Inter-VLAN routing and DHCP traffic passing. But not found concrete documentation on how to prevent this.

Any help appreciated.


Offline acejavelin

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Re: DHCP / VLAN problems since switch upgrades
« Reply #1 on: November 30, 2022, 10:31:02 PM »
Sounds like you have a loop somewhere... A PC port on a phone plugged back into a wall port that connects to another switch port perhaps.

Offline cenkozkan

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Re: DHCP / VLAN problems since switch upgrades
« Reply #2 on: December 01, 2022, 09:36:57 AM »
Sounds like you have a loop somewhere... A PC port on a phone plugged back into a wall port that connects to another switch port perhaps.

It is possible but wouldn't that have wider spread implications with spanning tree off?

Offline acejavelin

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Re: DHCP / VLAN problems since switch upgrades
« Reply #3 on: December 01, 2022, 10:27:24 PM »
Sounds like you have a loop somewhere... A PC port on a phone plugged back into a wall port that connects to another switch port perhaps.

It is possible but wouldn't that have wider spread implications with spanning tree off?
Not necessarily... The phone will only get DHCP from an option that is Mitel specific, the PC's won't care... It might be something else, but something, somewhere is "flattening" your VLAN's together as broadcast messages are hitting both servers and both are responding to the DHCP request.


 

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