dhcpv6 and logging CableLabs VSIO..

[Gregg Brzozowski]

I have a network (DOCSIS 2.0 + IPv6) where only the CPE is using DHCPv6 
to get an IP address.
Unless I use fixed assignments I have no working method of accounting 
for who has what IP address.

Fortunately, CableLabs seems to have specified a vendor specific 
information option for people that use modem mac addresses for 
accounting, option 36.
It's inserted by the relay agent, the CMTS. I have verified that the 
option exists by inspecting the SOLICIT packets from the CMTS. It's in 
the packet.

However, I am unable to log this option with dhcp v4.2.1.

Like most, I log the cable modem MAC with DHCPv4 and option 82.

When I try to do a similar thing in DHCPv6, nothing happens..
Bellow is my example configuration. I've only defined one option in the 
docsis space, device-id.

I've tried moving the "if exists" block into the subnet declarations, 
same result..

# Global definitions.
option space docsis code width 2 length width 2 hash size 17;
option vsio.docsis code 4491 = encapsulate docsis;
option docsis.device-id code 36 = string;

# Local nameserver, TunnelDHCP.
option dhcp6.name-servers 2607:3e00:0:722::66;
option dhcp6.domain-search "echoes.net";
option dhcp6.preference 255;
dhcpv6-lease-file-name "/usr/local/var/db/dhcpd6.leases";

if exists docsis.device-id
{
         log ( info, concat( "Lease is on modem: ",
         binary-to-ascii(16, 8, ":", option docsis.device-id)));
}

# JK CMTS
subnet6 2607:3e00:C000::/34 {
   range6 2607:3e00:c000:9001:: 2607:3e00:c000:ffff::;
   prefix6 2607:3e00:c000:c001:: 2607:3e00:c000:ffff:: /64;
}


...


Can anyone give me some guidance?



Thank you!

Gregg Brzozowski
Adams Cable