IPv6 behind router w/o PD

Installing and Using OpenWrt
1

I have this (German) Telekom Speedport Smart 2 for a VDSL connection. Behind that, I want to enable my network for IPv6. However, the Speedport Smart 2 does not support a Prefix delegation PD, it only supplies my router with a /64 network.

How can I enable this?

I already tried to 'relay' the IPV6 (in dhcp), but it does not to seem have the desired effect.

My PC gets IP addresses, but it seems not to route those correctly

	inet6 2003:e9:8703:ce69:cab:1e31:9c48:3f38 prefixlen 64 autoconf secured
	inet6 2003:e9:8703:ce69:36:760c:8508:9c4c prefixlen 64 autoconf temporary

ifstatus wan6
{
	"up": true,
	"pending": false,
	"available": true,
	"autostart": true,
	"dynamic": false,
	"uptime": 1446,
	"l3_device": "eth1",
	"proto": "dhcpv6",
	"device": "eth1",
	"metric": 0,
	"dns_metric": 0,
	"delegation": true,
	"ipv4-address": [

	],
	"ipv6-address": [
		{
			"address": "2003:e9:8703:ce69::1",
			"mask": 64,
			"preferred": 86399,
			"valid": 604799
		}
	],
	"ipv6-prefix": [

	],
	"ipv6-prefix-assignment": [

	],
	"route": [
		{
			"target": "2003:e9:8703:ce69::",
			"mask": 64,
			"nexthop": "::",
			"metric": 256,
			"valid": 604799,
			"source": "::/0"
		},
		{
			"target": "::",
			"mask": 0,
			"nexthop": "fe80::1",
			"metric": 384,
			"valid": 179,
			"source": "2003:e9:8703:ce69::1/64"
		}
	],
	"dns-server": [
		"fe80::1"
	],
...

Anyone having solved this issue?

2

P.S.: I can ping6 and traceroute6 from the router.

3

Does it have a valid default route to the ISP router?
Do ipv6 packets come out of the wan interface to the ISP router?

4

The short answer would be, you can't. DHCPv6-PD is required for proper routing, considering that the prefix is dynamically assigned (and changes after every reconnect) by DTAG (so static settings aren't possible.

A workaround using a BRouter setup can technically work, but it's really not a good idea. A proper solution would be to use a dedicated xDSL modem (maybe your current Speedport Smart 2 can be configured for PPPoE pass-through), your current router terminating the PPPoE session (and providing DHCPv6 and DHCPv6-PD) and (if needed) some other device handling your VoIP/ SIP needs (a (vendor supported-) low-end/ second hand AVM Fritz!Box (e.g. 7530) could be a good choice for that, those can be configured to IP client mode and provide the functionality of a SIP pbx, ATA and DECT base).

5

Just to clarify, the problem here is your current hardware (Telekom Speedport Smart 2), the ISP is handling IPv6 just fine (apart from only assigning highly volatile IPv6 /56 prefixes <-- that is inconvenient, and makes quite some things harder than they'd need to be, but this is a valid setup).

6

Thanks slh,
the modem can be configured as a modem only, but then I lose the DECT base station functionality.

I was hoping I could use an internal IPv6 network and route that to the outside world, akin to an IPv4 NAT.

If I understand you right, that is not possible, because the IPV6 prefix is changed frequently by the ISP (telekom)

7

After some research, I understood, that it is the fault of the Speedport Smart 2, being crippled, by not providing PD. As this is the house brand of Telekom, I don't consider this proper. Especially as this is not advertised.