Access Port Voice Data VLANs and DHCP

[Simon_Laffoley]

Hi All

I have a Meraki MS225 acting as an access switch having VLAN1 as Data and VLAN13 as Voice. I have separate DHCP Servers on each VLAN, VLAN1 as a windows DHCP Server. VLAN 13 as the phone system server.

I have a PC Only plugged into this port. Sometimes I get DHCP assigned IP from the voice vlan on the PC on startup. 

If I release and renew after login i get a correct IP Address allocated.

Why would this happen? would i need  to remove and add the voice vlan after every telephone move?

Any Ideas greatly received

[BrechtSchamp]

Did you configure your port correctly as shown here:

https://documentation.meraki.com/MS/Port_and_VLAN_Configuration/Configuring_the_MS_Access_Switch_for...

Only a phone would act on the LLDP advertisements the switch sends out announcing the voice VLAN and tag its packets with the voice VLAN tag. Assuming the rest of your VLAN configuration is correct DHCP requests tagged with the voice VLAN would then end up at the correct DHCP server.

A PC would send in the packets untagged upon which the switch would add the data VLAN tag to them. Then again they would end up at the correct DHCP server for the data VLAN.

[Simon_Laffoley]

Thats the weird thing. I have configured this many times using HP and Cisco and have never seen this before.

There is not much to the configuration, access port , data vlan ID, voice vlan ID.

trunk on the uplink with vlan 1 being native.

I can trunk the port with vlan1 native and data/voice as allowed but then I can't use 802.1x in a future access policy.

[BrechtSchamp · Accepted solution]

Hmm that's strange.

Whether or not you specify the allowed VLANs or have a full trunk shouldn't have an effect.

Are you sure that the phone DHCP server has no access to the data VLAN? I.e. ports connected to the servers set to access with the correct VLANs (don't use the voice VLAN feature on that side!)?

[Simon_Laffoley]

Yep my Bad

The Cisco Phone system was connected to a trunk native VLAN13 but also allowed Vlan1.

I've removed VLAN1 and we'll see how that goes.

Thanks

[ArshadSafrulla]

1st of all why are you configuring this port as a trunk? If it is connected to a phone it should be access port.

[Simon_Laffoley]

I agree handsets are best on an access port, but they can work in a trunk too.

I was referring to the cisco router part of the phone server solution providing DHCP that was trunked.

I don't know why it was setup as trunk as it only requires a single vlan, done before my time.