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Phone unregisters - DHCP renew fixes

Occasional Visitor

Phone unregisters - DHCP renew fixes

I have a few Polycom 321 and 450 SIP phones which are using a Cisco 800 series ADSL router. They get DHCP from this router. On a few occasions phone have individually unregistered. Rebooting the phone has no affect.


The only thing I have found that gets the phone working again is to clear the DHCP binding on the router then reboot the phone. The DHCP binding is still showing on the router before hand and I can see NAT translations etc on the router.


I've had no problems with other devices using the same router. Has anyone else seen this or have any idea what might be going on?



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Polycom Employee & Community Manager

Re: Phone unregisters - DHCP renew fixes

Hello MTDB,


welcome to the Polycom Community.


We encourage users to provide their SIP/UCS & BootROM /Updater Version in order to be able to cross check against release notes.


  • Are these other devices Polycom Phones and are they running the same software Version as the ones that do not show this behavior?
  • Did you check via a spanned/mirrored Port if the Phones, after a reboot are still sending a DHCP Request?
  • Can you still access the IP Address of the Phones to get on the HTTP Interface?
  • Did you check the registration Status as shown => here <=?

Best regards


Steffen Baier


Polycom Global Services

The title Polycom Employee & Community Manager is a community setting and does not reflect my role. I am just a simple volunteer in the community like everybody else. All posts and words are my own & do not represent the views of Employer.


Notice: This community forum is not an official Poly support resource, thus responses from Poly employees, partners, and customers alike are best-effort in attempts to share learned knowledge. If you need immediate and/or official assistance please open a service ticket through your proper support channels.
Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's
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