Issues in using User Class Option

Jain, Saurabh Saurabh.Jain at
Fri Dec 22 10:28:23 UTC 2017

On looking at the code seems like User-Class and Vendor-class are not supported for DHCPv6 in version 4.3.5 and 4.3.6

File common/tables.c

static struct option dhcpv6_options[] = {
                { "rapid-commit", "Z",                                    &dhcpv6_universe, 14, 1 },
#if 0
                /* XXX: user-class contents are of the form "StA" where the
                * integer describes the length of the text field.  We don't have
                * an atom for pre-determined-length octet strings yet, so we
                * can't quite do these two.
                { "user-class", "X",                                           &dhcpv6_universe, 15, 1 },
                { "vendor-class", "X",                                     &dhcpv6_universe, 16, 1 },
                { "vendor-opts", "Evsio.",                             &dhcpv6_universe, 17, 1 },

Is there any plan to support these DHCPv6 option in upcoming version?

Saurabh Jain

From: dhcp-users [mailto:dhcp-users-bounces at] On Behalf Of Jain, Saurabh
Sent: Friday, December 22, 2017 3:42 PM
To: Users of ISC DHCP
Subject: RE: Issues in using User Class Option

In the Server, I configured the class definition without making any change and got following error:

# Internet Systems Consortium DHCP Server 4.3.5
Copyright 2004-2016 Internet Systems Consortium.
All rights reserved.
For info, please visit
/etc/dhcp/dhcpd.conf line 113: no option named vendor-class in space dhcp6
    match if binary-to-ascii(10, 32, "", substring(option dhcp6.vendor-class,
Configuration file errors encountered -- exiting

If you think you have received this message due to a bug rather
than a configuration issue please read the section on submitting
bugs on either our web page at<> or in the README file
before submitting a bug.  These pages explain the proper
process and the information we find helpful for debugging..


Do I need to do some extra configuration?

Saurabh Jain

From: dhcp-users [mailto:dhcp-users-bounces at]<mailto:[mailto:dhcp-users-bounces at]> On Behalf Of Bill Shirley
Sent: Friday, December 15, 2017 12:07 PM
To: dhcp-users at<mailto:dhcp-users at>
Subject: Re: Issues in using User Class Option

I can't advise you on how to send option 16, but on the server you can check it:
# ------------------------------------------------------------------------------
class "Microsoft" {
    match if binary-to-ascii(10, 32, "", substring(option dhcp6.vendor-class, 0, 4)) = "311";
# ------------------------------------------------------------------------------

On 12/13/2017 5:17 AM, Jain, Saurabh wrote:
However,  when I look out options in DHCPv6 rfc 3315 and also other links I don't find a way to send vendor-class-identifier in solicit packets. In DHCPv4 it is option number 60 but no direct mapping in DHCPv6.  How do I send vendor-class-identifier in DHCPv6 ?


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