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Attention: The Community will be in read-only mode on 12/14/2017 from 12:00 am pacific to 11:30 am.

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New Member

Phone Registration - Mac Address Increase Needed

Strange one, I wondered if people had encountered it. We havent until recently and its random affects random users?

We have switchports set up with seperate voice and data vlans and a max of 3 macs

switchport access vlan 71

switchport mode access

switchport nonegotiate

switchport voice vlan 553

switchport port-security maximum 3

switchport port-security

auto qos voip cisco-phone

spanning-tree portfast

Users complain they are disconnected and the phone is trying to register. When you check the switchport the phone MAC is stuck in the native untagged vlan 1. Clearing MAC and port security does not work, Removing the voice vlan and adding it back does not work, however Increasing the Mac address Max command to 4 allows it to start using the Voice Vlan again and register.

Has anyone experienced this before? I guess I need span the port when it occurs again and pick apart a capture!

Cisco Employee

Phone Registration - Mac Address Increase Needed

What is the switch model and IOS version?

New Member

Phone Registration - Mac Address Increase Needed

Hi Joseph


IOS: c3750-ipbasek9-mz.122-58.SE2.

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