IPv6 setup on PPPoE

[beanybaby212]

I have been on the phone with BT technical team and the guy on the phone didn't know what PPPoE was. So here I am.

I have had EE smart hub connected with a pair of TP-links deco's handling the WiFi for a long time now.

IPv6 has been enabled the whole time and have not had any issues.

I have made the decision to want to remove the smart hub and only use my deco's as the main router to avoid any double NAT'ing and maybe, it might be better? Who knows. I also like the features when the deco's are in router mode so thats nice.

Anyway it became unstable and didn't really work until I disabled IPv6. Now it works perfectly fine in PPPoE mode so it seems my IPv6 settings are likely not correct to me.

So here are the options i have with the deco under IPv6:

connection type: PPPoE

sync IPv4 account = Enabled (username = bthomehub@btbroadband.com | Password =BT)

Get IPv6 address = Auto

Prefix Delegation = Enabled

DNS Address = Auto

Assigned Type = DHCPv6

I have read online I must set prefex delegation size to 56 but I do not see that option nor an option to change MTU size to 1500.

[licquorice]

You would be better asking on a TP Link forum.

BT IPv6 is /56 Prefix Delegation.

As far as I'm aware, the PPPoE settings are only required for IPv4 

[beanybaby212]

I already am trying to communicate with them and awaiting their response.

I must select a IPv6 connection type and the options are PPPoE, Dynamic IP(used when connected to my old Smart hub), 6to4 Tunnel, Bridge.

I understand this isn't a TP link forum but somebody must have used TP link devices in PPPoE mode

[licquorice]

Connection type should be Dynamic IP 

[beanybaby212]

I cannot use Dynamic IP as my deco unit is now my router, I do not have the smart hub connected at all.

IPv4 is connected in PPPoE mode which is needed to connect to my BT broadband, why should IPv6 be different?

[licquorice]

Because you authenticate via PPPoE which then gives you an IPv4 address. An IPv6 address is then allocated via Dynamic addressing.

[WSH]

Have a go at turning the DHCPv6 off.  If it's getting an IPv6 address native the usual arrangement would be to let your devices use SLAAC and not DHCP.

(And double NAT's an overrated issue.  It's only usually a problem if you host multiplayer games or run your own externally accessible servers).

[beanybaby212]

I have tried Dynamic IP and it wont retrieve any IP address it just does nothing, with PPPoE it does get an IP address.

According to few sources online BT uses DHCPv6? I have the option of choosing either ND Proxy, SLAAC+Stateless DHCP or SLAAC+RDNSS but I cannot just turn it off.

I understand your point, I have reached this point so far and I know it should work though.

[licquorice]

The DHCPv6 setting is the LAN configuration not the BT side. Set that to SLAAC and the devices should auto configure in line with the /56 Prefix received.

[beanybaby212]

I have changed to SLAAC but here is something else..

I have the option to 'Sync to IPv4 account' which I have had enabled. When this is like this I receive an IP address that I can read on my deco app. This is when the network is very unstable. If I untick Sync and manually enter the same username and password on the IPv4 side I no longer get an IP address, the internet is then fine but assuming all this does is act like I have disabled it.

This is looking like a TP link issue more and more