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DHCP vendor ID

Question

Tuesday, April 17, 2012 8:53 AM

Hello

I need Polycom phones to be given a specific set of IPs. There are approximate 100 phones.

I have searched(to start). The nearest one (using 2008 server) is

http://social.technet.microsoft.com/Forums/en-US/winservergen/thread/b50761ca-116c-4be9-b3a6-9eb4f804671a

There is no clear thread which defines how to use Vendor ID and then link it to specific scope. We are using 2008 R2.

To start with, typical of Poycom, I dont know what the vendor ID looks like(conflicting info everywhere). We have mix of Polycom lot - So just need a specific string(binary) to identify its poycom.

Does MS DHCP work in a way so that anything 0004fxxxxx (This is polycom mac) is identified and put in separate scope? Why even Vendor ID thing comes into play when we all know that MAC addresses identify the company.

All replies (10)

Thursday, April 19, 2012 2:20 AM ✅Answered

Hi Nitin,

Thanks for posting here.

According the descriptions in the polycom official document , the data format of DHCP option 60 of their products should be :

The DHCP option 60 data can appear in two formats:

  • ASCII String format is “Polycom-” + <value of hardware board model name>. For example, for a SoundPoint IP 560, the data would show “Polycom-SPIP560”.

Using DHCP Vendor Identifying Options with Polycom Phones

http://support.polycom.com/global/documents/support/technical/products/voice/DHCP_Option_60_TB54041.pdf

Could you confirm with Polycom support service about that ?

Regards,

Tiger Li

TechNet Subscriber Support in forum

If you have any feedback on our support, please contact  [email protected].

Tiger Li

TechNet Community Support

Tuesday, April 17, 2012 1:15 PM

Not that I have seen, you typically want to segment IP phones from your PC/Servers/etc using VLANs and then your helper forwarder would send the DHCP request to your server.  Your DHCP server would then see the VLAN information in the packet and use the appropriate scope to pull addresses from.

Typically from what I've seen, as long as your IP phones are 'corraled' in specific VLANs, it doesn't really matter what the IP address is since they are typically provisioned from the phone system by the MAC address.

Wednesday, April 18, 2012 6:36 AM

Hi Nitin,

Thanks for posting here.

Maybe the callout dll will help to achieve that , please refer to the blog post below:

Option based IP Address assignment Callout Dll

http://blogs.technet.com/b/teamdhcp/archive/2009/06/12/option-based-ip-address-assignment-callout-dll.aspx

Regards,

Tiger Li

TechNet Subscriber Support in forum

If you have any feedback on our support, please contact  [email protected].

Tiger Li

TechNet Community Support

Wednesday, April 18, 2012 1:18 PM

That is cool, I can't believe I have never seen that package.  Thanks Tiger.

Wednesday, April 18, 2012 6:02 PM

Hi Nitin,

Thanks for posting here.

Maybe the callout dll will help to achieve that , please refer to the blog post below:

Option based IP Address assignment Callout Dll

http://blogs.technet.com/b/teamdhcp/archive/2009/06/12/option-based-ip-address-assignment-callout-dll.aspx

Regards,

Tiger Li

TechNet Subscriber Support in forum

If you have any feedback on our support, please contact  [email protected].

Tiger Li

TechNet Community Support

Dear Tiger Li

The callout dll is not required in R2. Its integrated in R2.

Other than that I think google usually helps and therefore ofcourse I am aware of this link(It should work w/o registering the dll)

My question (which is not answered) is Polycom string. Polycom has poor quality documentation(I think most of the stuff is for their partners, not end clients to access) and therefore no clear way exists.

Also, on MS part, the vendor string is Binary/Ascii or other - Thnings are quite muddy here.

Thursday, April 19, 2012 11:06 AM

Dear Tiger Li

Thanks for the link - I couldnot find it earlier - This i had a "hint" after reading the link I posted in first post(where user has decribed how Polycom "helped" him by changing the default format to ASCII)

(I cannot ask Polycom - I dont have support contract - I have already ranted about how a few companies like Polycom are still living in 1900s and donot let users have access to proper documentation)

The link is very useful becasue now we will know which phone is behaving which way (100 phones - i am bound to see diferent firmware)

Let me ask for a very specific help -

a) How to implement option 60 using rfc3295.

b) Polycom has 13885(octet 00 00 36 3d) assigned.  How do we use this and hand out address from specific scope when DHCP server ses this vendor ID.

So, I see that each and every Polycom will give out this octet. How do we use this as vendor ID?

And on a side note - Why Vendor ID even exists for DHCP? Wouldnt it be far easier if DHCP had some option that if MAC address has 00 04 xx then assign this scope, else if another mac then this scope - and so on. MAC address have been used to identify the vendor since ages..

Thursday, April 19, 2012 11:59 AM

Hi Nitin,

Thanks for update.

Yes we’ve aware of such requirement before so made this improvement in next generation “Windows Server 2012”, the DHCP Policy-based Assignment feature will active that easily :

Step-by-Step: Configure DHCP Using Policy-based Assignment
http://technet.microsoft.com/en-us/library/hh831538.aspx

The binary should be automatically generated once we input ASCII code: 

Thanks.

Tiger Li

Tiger Li

TechNet Community Support

Friday, April 20, 2012 9:03 AM

Hi Nitin,

Please feel free to let us know if the information was helpful to you.

Regards,

Tiger Li

TechNet Subscriber Support in forum
If you have any feedback on our support, please contact  [email protected].

Tiger Li

TechNet Community Support

Thursday, August 23, 2012 4:59 AM

Hi,

I am heading down a similar path.

I have used another DHCP server to achieve the end I want, but I wonder if the windows dhcpd can do it more neatly.

My network looks like this:

  • 192.168.2.x/16 - phones
  • 192.168.1.x/16 - everyday computers
  • (not DHCP-related) 192.168.3.x/16 - servers/routers etc
  • gw at 192.168.3.254/16

So, I'd like to define two scopes 192.168.1.10-199/16 and 192.168.2.100-199/16. And I can't because the tool says "The address range and mask conflict with an existing scope".

Why?  They are not overlapping. Yes they are on the same subnet, but so what? It is odd, but it is not wrong. With these two scopes, the DHCP server could/should just hand out addresses from either/both scopes. (Though I agree, I can't imagine why anyone would want to do that...).

<rant> And, speaking of wrong. If I define a 24bit scope (192.168.1.10-199/24), the tool lets me define an unreachable router (192.168.3.254) for that scope, and it says nothing to me about my mistake. That is, the tool stops me doing something right(ish) and doesn't stop me doing something (completely) wrong.  (!) </rant>

But, and in any case. I want to disambiguate using VendorID. I'd like to separate the two scopes by saying something like : 

IF vendorclass=='SEC_ITP' THEN scope1 ELSE scope2

Here is how it looks on my existing server. Is it possible to do this on the windows dhcpd or should I accept defeat?

[SETTINGS]
; First pool is for the phone handsets.
IPPOOL_1=192.168.2.10-250
IPBIND_1=192.168.3.150
IPSCOPE_1=if(vendorclass=="SEC_ITP","PHONES",null);
; ...[PHONES]
; lease time is 40 days
LEASETIME=3456000
SUBNETMASK=255.255.0.0
NEXTSERVER=192.168.3.151
OPTION_128=192.168.2.1; officeserve box
; ...

Tuesday, December 25, 2012 6:06 AM

@Sam.Lander: You can reserve portions of subnet to specific devices using DHCP policies in WS2012. Check the blog below for further details:

http://blogs.technet.com/b/teamdhcp/archive/2012/08/22/granular-dhcp-server-administration-using-dhcp-policies-in-windows-server-2012.aspx

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