DHCP Server configuration document for Poly VVX-series phones to force registration to ZoomPhone

[avshch]

Hello,

Could Zoom put a document together on how to configure DHCP Server with supported DHCP options for Poly VVX series phones?

Thanks,

[djrnb]

I don't expect Zoom will document this given Poly is the manufacturer. This may be of some help: https://community.polycom.com/t5/VoIP-SIP-Phones/DHCP-Standardization-160-vs-66/td-p/72577

[avshch]

Indeed! Why would Zoom help their own customers!? lol Polycom article does not mention how the phones communicate to Polycom ZTP (Zero Touch Provisioning). That's where the problem is with the phones behind a firewall.

[BrandonS]

But you don’t use custom DHCP options _and_ ZTP. If ZTP is not working then your firewall is blocking communication to Poly and Zoom servers or a typo of MAC address in your Zoom admin portal. Custom DHCP would be used to ease the provisioning of non ZTP supported phones. 

[avshch]

@BrandonS Yup. I know that. I just can't find what's needed (from Firewall perspective) for the phones in order to register to ZTP. Was not able to find anything on Poly site. Any ideas?

[BrandonS]

 Basics are here: https://support.zoom.us/hc/en-us/articles/201362683-Zoom-network-firewall-or-proxy-server-settings

try bypassing your firewall or take a phone home to prove the point.  The basic process is that you first enter MAC address in your Zoom admin portal and then factory default phones if not new in box. Then they reach out to Poly’s ZTP server to get provisioning details and then update firmware and register with Zoom. If you have restrictive firewall policies they might be blocking something required for this to work. 

[avshch]

I have a ticket with Zoom Support, but they are asking me for the packet capture. Sounds like they don't have any documentation they can provide.

[jsteinberg]

Is your question around firewall rules needed, or how to set provisioning addresses via DHCP ? 

If you are wanting to do provisioning via DHCP options, you can set the DHCP option ( e.g. option 66 ) to the Zoom Assisted Provisioning URLS., which you can see here https://support.zoom.us/hc/en-us/articles/360038910791-Assisted-provisioning-URLs

Firewall requirements are listed here - https://support.zoom.us/hc/en-us/articles/201362683-Zoom-network-firewall-or-proxy-server-settings

[avshch]

@jsteinberg thank you for the links.

Setting DHCP Option 66 = https://provpp.zoom.us/api/v2/pbx/provisioning/Polycom/vvx250 does not help Poly VVX 250 to boot.

The link with the firewall ports references does not have ZTP or NTP requirements.

[jsteinberg]

If your phone has old firmware, it might have an old certificate trust store and therefore not be able to trust the Zoom provisioning servers.  You could try to upgrade the phone firmware manually first, then try again.

Putting the provisioning server addresses in DHCP option 66 will work.    Can you try to factory reset the phone ?

If you have internally NTP servers, they are not required to open a firewall rule.  So that varies by network.

If your firewall is blocking all outbound internet connections, you will need to add rules to allow the phone to talk to the Zoom cloud as detailed in the firewall link.