You are here

DHCPv6 address assignment


Hi evereyone,

If i want to assign IPv6 to CPE and use CM MAC as a identifier to assign different subnet.

I have try ISC dhcp 4.2, but I can not find a way to accomplish it.

Is there any open source dhcp server support thie feature?

Please give me some suggestion,thanks

Static IP / subnets are normally linked to CPE rather than cm.

Is the CPE a router? If so perhaps use IPv6 prefix delegation for the subnet. Recent versions of ISC dhcpd support PD.

This is an example I typed up for someone else recently who was asking about DHCPv6.... :

1) Run a recent IOS on your CMTS eg 12.2SCE or even better SCF

2) You need to run CableLabs "eRouter" compliant firmware on the gateway. Most vendors (Arris, Cisco, Motorola) now have this in their latest firmware builds.

3) You need to setup and run a DHCPv6 server such as isc-dhcpd. (Or a recent commercial product like Cisco CNR/BACC or Incognito BCC). Something like this :

ddns-update-style none;

option xxxx:xxxx:xxxx:200::100, xxxx:xxxx:xxxx:300::100;
option dhcp6.preference 255;
option dhcp6.rapid-commit;

# match the eth0 subnet for dhcp server
subnet6 xxxx:xxxx:xxxx:200::/64 {}

# match the bundle subnet for cmts
subnet6 xxxx:xxxx:xxxx:100::/64 {
# dynamic ip's here.
# The (IA-NA) IP's handed out will be randomised (not EUI-64) for privacy reasons
# It takes the client-id and hashes it with MD5 to generare an IP address
range6 xxxx:xxxx:xxxx:100::1:0 xxxx:xxxx:xxxx:100:ffff:ffff:ffff:ffff;

# RFC3633 IA-PD
# delegate /56's from this /40 block (65K /56's, a /56 is 256 /64's)
prefix6 xxxx:xxxx:yy00:: xxxx:xxxx:yyFF:FF00:: /56;

4) Configure the CMTS bundle to run in DHCPv6 mode like this :

ipv6 address xxxx:xxxx:xxxx:100::1/64
ipv6 enable
ipv6 traffic-filter CABLE-IN-V6 in
ipv6 traffic-filter CABLE-OUT-V6 out
ipv6 nd prefix default no-advertise
ipv6 nd managed-config-flag
ipv6 nd other-config-flag
ipv6 nd ra interval 5
ipv6 dhcp relay destination xxxx:xxxx:xxxx:200::50

So in this example the eRouter will get a /64 WAN IP, plus if it requests PD it will be given a /56. The eRouter will then allocate a /64 to it's LAN interface and usually do stateless autoconfig for the local clients.