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ralphrmartin
Contributor
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Message 1 of 17

Smart Hub Bug - IPv6 Pinholes

Has anyone else tried to use IPv6 pinholes? There is a serious bug in the BT Smart Hub which prevents them from being useful.

 

 

The way they should work:

Each separate pinhole should allow traffic through from external devices to a desired port on a specified host, using its permanent IPv6 address.

Thus, it should be possible to create pinholes on several different hosts, each to its own port 23, say.

 

The way the BT Smart Hub actually works:

Pinholes have been set up like IPv4 port forwarding.

IPv6 traffic for a given port number, 23 say, can only be sent to one IPv6 host.

 

This defeats the whole point of IPv6 pinholes. 

 

They should not be treated in the same way as IPv4 port forwarding - as there is only one IPv4 address, traffic for a given port can only be forwarded to one device.

With IPv6, each device gets its own address, so the same port can be used on all devices - or at least could, if there were not this bug in the Smart Hub.

 

There seems to be no official way to report bugs to BT, so I am posting this here in the hope that someone within BT sees this and reports it to the appropriate engineering team.

 

 

 

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16 REPLIES 16
smf22
Recognised Expert
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Message 2 of 17

Re: Smart Hub Bug - IPv6 Pinholes

I don't use the Smart Hub, but your post made me curious so I've dragged one out of the drawer to see what the options were. On this one, albeit running the very old SG4B100021EC firmware, it does behave the way you've described but even more alarmingly only allows devices to be selected from a list that identifies the device by IPv4 address and MAC address. Do you see the same option or has this changed in later firmware?

 

Given the above, there are several problems that may arise irrespective of the behaviour you've highlighted:

 

- Clearly the Hub can't be saving an IPv4 address in an IPv6 pinhole, so we have to assume it saves something else. As the Hub knows the clients MAC address it could derive the EUI-64 address and save that, but Windows for example doesn't use EUI-64 so this isn't guaranteed to work.


- If the saved IPv6 pinhole also contains the IPv6 prefix, then the pinhole will stop working when the Hub is delegated a different IPv6 prefix. Unless of course it's smart enough to update the pinholes with the new IPv6 prefix.

 

As I see it you need a router that would allow you to specify a 'wildcard' in the IPv6 network portion of the address, and allow free form configuration of the host portion of the address. I think it's unlikely any ISP router would have such flexibility and that perhaps purchasing a third party router would be the better option in your case.

 

Regards

ralphrmartin
Contributor
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Message 3 of 17

Re: Smart Hub Bug - IPv6 Pinholes

On current hardware, it lets me select the device from a list of devices identified by name. If the name is tied to a MAC address, that should not be a problem - in principle, devices should not change their MAC addresses (normally - unless there is a repair, hardware upgrade etc). I don't see that IPv4 has to come into it, but I don't have any IPv6-only device to try.

 

However, I dont see why BT can't, and indeed would not, give people permanent IPv6 addresses. There is no advantage to them whatsoever in not making them static, tied to your phone number. In practice mine has never changed. BT appear to say nothing as to whether they do in fact change them. Even if the hub does update the IPv6 prefix for the pinhole, it also means I would need to use dynamic DNS to access the devices, which is an unnecessary effort.

 

(A much worse problem is that I only get IPv6 connectivity on about 1 in 3 reboots of my router. I cannot get BT's fault reporting service to even understand what I am talking about, far less accept that there is a fault. I checked my terms and conditions and they say absolutely nothing about IPv6).

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Distinguished Sage
Distinguished Sage
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Message 4 of 17

Re: Smart Hub Bug - IPv6 Pinholes


@ralphrmartin wrote:

 

 

However, I dont see why BT can't, and indeed would not, give people permanent IPv6 addresses. There is no advantage to them whatsoever in not making them static, tied to your phone number. In practice mine has never changed. BT appear to say nothing as to whether they do in fact change them.


I rather suspect it is so they can still charge a premium for static addresses.

 

Understandable for IPv4 but nonsense for IPv6

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smf22
Recognised Expert
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Message 5 of 17

Re: Smart Hub Bug - IPv6 Pinholes


@ralphrmartin wrote:

On current hardware, it lets me select the device from a list of devices identified by name. If the name is tied to a MAC address, that should not be a problem - in principle, devices should not change their MAC addresses (normally - unless there is a repair, hardware upgrade etc). I don't see that IPv4 has to come into it, but I don't have any IPv6-only device to try.

 


So has the way the devices are identified in the list has changed in newer firmware i.e., it no longer shows the IPv4 and MAC address as per the below?

 

bt_hh6_ipv6_pinhole.png

 

That's better than what I saw, but unfortunately it still seems to not let us see what address it's saved. This means there's no way to be certain you'll not run into the problems I mentioned.

 


@ralphrmartin wrote:

(A much worse problem is that I only get IPv6 connectivity on about 1 in 3 reboots of my router. I cannot get BT's fault reporting service to even understand what I am talking about, far less accept that there is a fault. I checked my terms and conditions and they say absolutely nothing about IPv6).


I've been using IPv6 on a Ubiquiti router since last October and have never had any issues with loss of IPv6. This isn't just observed through casual use..... I know this for a fact as I have IPv6 smokeping probes running 24x7 and can see there's been no IPv6 loss. I think the intermittent IPv6 people are seeing is related to a bug in the Hub 6 firmware so maybe the problem will be fixed in the next release.

 

Regards

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ralphrmartin
Contributor
3,144 Views
Message 6 of 17

Re: Smart Hub Bug - IPv6 Pinholes

Yes, the UI is now different:

 

Screen Shot 2017-05-27 at 12.47.42.jpg

 

As for broken IPv6 connectivity - yes, I also have a Fritzbox in use elsewhere. I may try bringing it here and see if that fixes the connectivity issue.

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ralphrmartin
Contributor
3,141 Views
Message 7 of 17

Re: Smart Hub Bug - IPv6 Pinholes

Screen Shot 2017-05-27 at 12.50.57.jpg

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jeffreysmith
Aspiring Contributor
2,764 Views
Message 8 of 17

Re: Smart Hub Bug - IPv6 Pinholes

Having exacly the same issue, Trying to open ssh on two machines to the internet but I get the following error when I try to add the second rule that uses port 22. 

pinholeError.JPG

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Liam_
Expert
2,757 Views
Message 9 of 17

Re: Smart Hub Bug - IPv6 Pinholes

It would seem from the behaviour detailed above that IPv6 port forwarding on the Hub 6 is fundamentally flawed.  Looks like the best solution is getting your own third party router, rather than rely on a future firmware fix curing the problem. Some recent firmware updates, going by posts in the forum, have caused more issues than they have fixed.

A proper router would handle IPv6 port forwarding/pinholes, whatever term you prefer, by using the device interface ID and assigning a new prefix whenever the delegated dynamic prefix changed.

More than one instance of identical ports can be forwarded on my router, a FritzBox, tested with 3 PCs all having ports 21, 990 and the 50000 - 50500 range forwarded.

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drgeoff
Beginner
2,116 Views
Message 10 of 17

Re: Smart Hub Bug - IPv6 Pinholes

pinholes.pngI have a Hub 6B with firmware v0.09.05.11160-BT.  I am able to forward the same port to multiple IPv6 devices.

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