CableLabs Vendor Specific Option not in Relay-Reply message

Cheng Ching-Ho-LCC014 Ching-Ho.Cheng at
Mon Oct 4 13:50:37 UTC 2010

Thanks for your response.  I tried to avoid repetition of DOCSIS
specific options in different subnet6 definitions.  We have many
machines accessing the DHCPv6 servers.  That's why we defined all these
options globally.  It used to work for us in 4.0.x ISC DHCPv6 server.
Now, after I upgrade to 4.1.1-P1, it does not work any more -
relay-reply message from server does not contain DOCSIS specific options
Any other suggestion is appreciated.
Ching-Ho Cheng


From: at
[ at] On Behalf
Of Patricio Latini
Sent: Sunday, October 03, 2010 4:20 PM
To: dhcp-users at
Subject: RE: CableLabs Vendor Specific Option not in Relay-Reply message

I think you should include the options within the subnet definition.
LIke the example below. That is working for me.

shared-network C4-IPV6-Bundle1 {
subnet6 FC00:0000:0000:0001::0/64 {
option docsis.tftp-servers FC00::1;
option docsis.cablelabs-configuration-file "arris-D30modem.bin";
option docsis.cablelabs-syslog-servers FC00::1;
option docsis.time-servers FC00::1;
option docsis.time-offset -10800;
option FC00::1;
range6 FC00:0000:0000:0001::/64;


Subject: RE: CableLabs Vendor Specific Option not in Relay-Reply message
Date: Thu, 30 Sep 2010 10:22:43 -0400
From: Ching-Ho.Cheng at
To: dhcp-users at

I have enclosed the dhcpd6.conf for reference.  I hope that this could
help to determine my DHCPv6 server problem :
#Define the options:
option space docsis code width 2 length width 2;
option vsio.docsis code 4491 = encapsulate docsis;
option docsis.tftp-servers code 32 = array of ip6-address;
option docsis.cablelabs-configuration-file code 33 = text;
option docsis.cablelabs-syslog-servers code 34 = array of ip6-address;
option docsis.device-id code 36 = string;
option docsis.time-servers code 37 = array of ip6-address;
option docsis.time-offset code 38 = signed integer 32;
#Configure global options:
option docsis.cablelabs-configuration-file "basic.bin";
option docsis.cablelabs-syslog-servers 2000:300::2;
option docsis.tftp-servers 2000:300::2;
option docsis.time-servers 2000:300::2;
option docsis.time-offset 0;
option dhcp6.rapid-commit;
# lease-time information: default = 30 minutes, max = 120 minutes
#default-lease-time 864000;
#max-lease-time 864000;
default-lease-time 1800;
max-lease-time 1800;
# modem configuration file name:
#filename "basic.bin";
ddns-update-style ad-hoc;
    subnet6 2000:300::/64 {
            range6 2000:300::/64;
# Goldie Subnet 
shared-network "goldie_1" {
        option docsis.cablelabs-configuration-file "goldie_1.bin";
        subnet6 2001:100:101::/64 {
                range6 2001:100:101::/64;

Ching-Ho Cheng


From: at
[ at] On Behalf
Of Cheng Ching-Ho-LCC014
Sent: Wednesday, September 29, 2010 2:01 PM
To: Users of ISC DHCP
Subject: CableLabs Vendor Specific Option not in Relay-Reply message

I upgraded the DHCP server to 4.1.x from 4.0.x. Now, in DHCPv6
relay-reply message from ISC server, there is no CableLabs vendor
specific options included. IPv6 modem could not register due to the
missing TFTP/config file information within the CableLabs vendor option.

I was using the same dhcpd6.conf as in 4.0.x. Any suggestion is

Ching-Ho Cheng
Motorola Inc.
Mobile Devices & Home
Phone: 508-786-7522

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