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Full Version: CDP enable after factory reset cause the phone can't obtain IP address
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I have a situation here after upgrading to latest V83 firmware on my T23G phone.

Previously, each time I reset to factory, the phone can obtain IP address from DHCP service without problem.

Recently, I discover that reset to factory, some phone can obtain IP address but some phone can't.

After further investigation, I notice those phone connect directly to core switch can get IP address. For those phone connect to access switch or nested switch, it can't get the IP address.

I further notice that if the cdp was enable in this new firmware. If I set the cdp enable to false explicitly after factory reset, I can get IP address for phones connected to access switch.

Please rectify this problem.

Thank you.
Are you connecting phones to Cisco switches? If so, do you have CDP configured on your switches?

If setting CDP to disabled on the phone solves the problem, that is usually an indicator that you are using Cisco switches with default Voice VLAN/CDP advertising setup. If you do not want this/aren't using it, you should be turning it off on your switch, not relying on the phones to ignore it...
No. I am using Dell-x1052P as core switch and some mix managed or unmanaged switch as access switch.

Never aware the core switch has CDP option. Will try it later.
After a week of trial and error, no matter how I tweak the configuration, the phone will only obtain IP address with CDP disabled if it is connected to nested switch.
(It can obtain IP address successfully with CDP enabled only if connected to the main switch directly.)
I am not using a Cisco switch nor there is any Cisco devices in the network, so I decided to downgrade the firmware of the phone itself.

After downgrading to the previous firmware, even with CDP enabled by default, it is still able to obtain the IP address without any issues after factory reset or rebooting.
Current Firmware: T23-44.84.0.10.rom
Previous Firmware: T23-44.83.0.50.rom

Wish to know if this is a bug or intended behaviour.
Thank you.
At this point if you have confirmed it's something that has changed in firmware you should probably open a support ticket for it, you will get better response from Yealink staff than here in the forums.
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