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Invalid IP config from DHCP Option 43

SOLVED
Occasional Advisor

Invalid IP config from DHCP Option 43

I am seeing an issue on VVX phones, specifically 500/600, when a DHCP Option 43 offer intended for the MS-UC-Client vendor class is sent by the DHCP server even when not requested. The issue is that an invalid subnet mask, gateway and time offset info is configured on the Polycom phone.

 

During the phone bootup I can see the following in a Wireshark trace:

 

  1. VVX models send a request for option 43 during bootup, advertising its own vendor class ID in Option 60 (i.e. Polycom-VVX600)
  2. With the device in the Lync profile mode and when PIN auth is attempted to Lync, another Option 43 Request/Inform is sent from the device with the typical MS-UC-Client ID in option 60 to obtain Lync specific values.

 

This particular client’s DHCP server (QIP in this case) is sending the Option 43 for MS-UC-Client in every standard DHCP Offer, regardless of the vendor class in Option 60. This is different than what I have seen with a Microsoft DHCP or Linux-based server in that only Option 43 is sent in the Offer response if it matches what the client/device asked for. Per RFC 2132 the DHCP server SHOULD respond with the vendor class requested but it doesn’t seem this is a requirement. We are going back to the DHCP vendor to review the behavior but I’m posting this note here because only the Polycom phones have an issue with getting this “non-requested” Option 43 info.

 

Other vendor devices and even the Windows client appear to just discard the info since it was not requested. The Polycom phones receive this info and the result is an invalid IP configuration. Most DHCP options such as DNS, NTP and other info is correct but the mask becomes a value such as 77.83.x.x, the gateway is 108.121.x.x and the GMT offset is a very long value. As such the phones are not communicating on the network. A static IP resolves the issues but obviously that is not the course we want to go down.

 

I can also reproduce this by using a Microsoft DHCP server to push the standard Lync Option 43 sub-options for MS-UC-Client to the VVX phones by changing the vendor class ID to Polycom-VVX600 (for example).  While it could be argued that the DHCP server is at fault here other vendor devices are ok. We may not be able to get a fix for this from the DHCP vendor so would be looking to Polycom on why the phone is configuring itself in this way.

Message 1 of 5
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Polycom Employee & Community Manager

Re: Invalid IP config from DHCP Option 43

Hello kwall,

welcome to the Polycom Community.

It is always useful to include the currently used software version as issues experienced may already be addressed in a newer release.

This also allows yourself and others to check against current software release notes.

Therefore the Polycom VoIP FAQ contains this post here:

Question: How can I find out my SIP UC Software Version or the BootROM Version of my Phone?
Resolution: Please check here

Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services




<======== Signature / Disclaimer ========>
Please be aware:For questions about the type of support to expect please check here

Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's

Please remember, if you see a post that helped you , and it answers your question, please mark it as an "Accept as Solution".

The title Polycom Employee & Community Manager is an automatic setting within the community and any forum reply or post is based upon my personal experience and does not reflect the opinion or view of my employer.
Poly employee participation within this community is not mandatory and any post or FAQ article provided by myself is done either during my working hours or outside working hours, in my private time, and maybe answered on weekends, bank holidays or personal holidays.
Message 2 of 5
Occasional Advisor

Re: Invalid IP config from DHCP Option 43

Thanks Steffen, good point.  The current version info is below:

 

Part Number 3111-44600-001 Rev:A 
UC Software Version 4.1.2.26872 
BootROM Software Version 5.1.2.1133

Message 3 of 5
Polycom Employee & Community Manager

Re: Invalid IP config from DHCP Option 43

Hello kwall,

please upgrade to a currently supported software version.

 

UCS 5.2.0 for example


Please ensure to provide some feedback if this reply has helped you so other users can profit from your experience.

Best Regards

Steffen Baier

Polycom Global Services




<======== Signature / Disclaimer ========>
Please be aware:For questions about the type of support to expect please check here

Please also ensure you always check the VoIP , Video Endpoint , Skype for Business , PSTN or RPM FAQ's

Please remember, if you see a post that helped you , and it answers your question, please mark it as an "Accept as Solution".

The title Polycom Employee & Community Manager is an automatic setting within the community and any forum reply or post is based upon my personal experience and does not reflect the opinion or view of my employer.
Poly employee participation within this community is not mandatory and any post or FAQ article provided by myself is done either during my working hours or outside working hours, in my private time, and maybe answered on weekends, bank holidays or personal holidays.
Message 4 of 5
Occasional Advisor

Re: Invalid IP config from DHCP Option 43

Thanks Steffen.  If I had known it would be that easy I would have done that earlier!  I misread the different version numbers and thought we had a much more updated UCS package than we really did.  I applied the 5.2.0 package via the provisioning server and that resolved the issue.

Message 5 of 5