unknown protocol drops on switch port with Cisco phone

[RFC_2549]

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Hello,

I have a Customer that plugged a malfuncioning phone (not registering) after resetting it to factory settings in two different ports of a Cisco 2960 switch. The ports are correctly configured, the phone Is not registering (he don't even took an IP via DHCP) and I see a lot of "unknown protocol drops" on both ports increasing in number when he plugs the phone. What can be causing this? What can we try? They dont'have a sostituire phone, on the same switch there are more phones, all correctly working

Thank You

[djl]

Check your IPoAC settings. ; )

Sorry, I don't actually have anything to add to this, just appreciate your username.

DJ

[Leo Laohoo]

Is the phone even getting a valid IP address?

[RFC_2549]

No, he has no IP address

Thank You

[Leo Laohoo]

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@RFC_2549 wrote:

No, he has no IP address

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Good.  You've now determined what has happened to the phone and why it is not registering.  
What is the next troubleshooting step?

[RFC_2549]

I knwe why it was not registrering, also I writed this info in the original post. My question was about the "unknown protocol drops" on the port

Thank You

[Leo Laohoo]

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@RFC_2549 wrote:

I knwe why it was not registrering, also I writed this info in the original post. My question was about the "unknown protocol drops" on the port

Thank You

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Unknown protocol drops is usually attributed to DTP.  
Is the port a Trunk port?

[RFC_2549]

Hello, the port was in access, the problem was solved changing the phone