IPv6 Trial Update

[#1]

@Stuper yeah you should be fine, even if you switch speeds the IPv6 should remain as it's hard coded to the account regardless of which broadband product you have. The only time I've seen an account lose it was when they changed broadband firewall settings because the 2 are currently stored in the same database table and it accidentally got overwritten but was easy to put back (it's just inserting a pair of numbers into the table).

[#2]

@dave ,

Is there a way I can troublehoot the PlusNet IPv6 connection?  
My original "router" was a now fairly old Juniper SRX that I had been using with a HE tunnel.  The SRX picked up the new delegation OK but didnt distribute the IPv6 delegation properly and started dropping off the network on a regular basis.  Probably long in the tooth and needed newer firmwares which I dont have access to.  So I replaced it with a UniFi UCG.  That went well, picked up the delegation and just worked until this weekend when I lost all IPv6 connectivity. Total loss.  IPv4 remained fine.  No software or firmware updates had been applied.  I have had to swap the router back out to the old SRX.  My old HE IPv6 tunnel came straight back to life but to be honest I am now a little non the wiser as to how to troubleshoot the PlusNet IPv6.
Are there any suggestions, or is there a way to get the IPv6 checked at the PlusNet end?  Ideally I would like to understand what went wrong before I go out an make yet another purchase.  Or spend too much time fiddling with it.
Thanks in advance for any troubleshooting suggestions

Will.

[#3]

One other issue I saw I would welcome comments from anyone on:

I saw that the Plusnet IPv6 was only applying a link local address towards the internet.  I am fine with that.  from a routing perspective I understand that works.  But I then saw that my UniFi gateway was trying to connect to DNS servers via the first internal interface gateway address, which reflected back and then got blocked.  So internal addresses were showing blocked as inbound traffic having come from the external link.  And so the UniFi gateway was not working with external DNS servers on IPv6 addresses.

Is the above a bug in the router, or expected behaviour for this architecture?

[#4]

I haven't yet moved my UGC in place of a debian-based router, but I did notice that I wasn't getting a reply via dhcpv6, only from prefix delegation.

Given I can customise the debian setup, I just manually (and statically as prefixes don't change) mapped the prefix::1 address to the ppp0 interface and then everything worked as expected / IP6-ping from outside to prefix::1 was ok, etc.

Hope that's helpful.

https://community.plus.net/t5/IPv6-Trial/IPv6-Trial-Update/m-p/2006979#M3450 was where I first wrote about this.

[#5]

Thanks for the heads-up.  I will take a closer look later.  If the prefix::1 works on the ppp0 I can see how that might solve both of my above issues!  I think prefix::1 got assigned by the UCG to my main subnet.  Lets see.

[#6]

I got a /56 prefix configured by Dave.

So aaaa:aaaa:aaaa:aabb:cccc:cccc:cccc:cccc

I kept bb=00 for the external/uplink side, and used aaaa:aaaa:aaaa:aa00:0000:0000:0000:0001 for the external address.

I can't see it should make any difference at all which of the delegated /64's you choose to use on the uplink though, as long as you're careful about the firewalling setup.

I can't really advise about that yet though as making time to familiarise myself properly with unifi firewalling is still on my to-do list, and I'm actually a bit grumpy that it appears to have to be done via the GUI rather than command line.

Good luck!

PS. There's also https://homepages.plus.net/dtomlinson/ping_graphs.html where some of us have monitoring configured.  It's great for a quick look to see if something's widespread or just local.

There was a post about it earlier in the thread.  It uses https://www.thinkbroadband.com/my-profile/login 

[#7]

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@MPC wrote:

I haven't yet moved my UGC in place of a debian-based router, but I did notice that I wasn't getting a reply via dhcpv6, only from prefix delegation.

Given I can customise the debian setup, I just manually (and statically as prefixes don't change) mapped the prefix::1 address to the ppp0 interface and then everything worked as expected / IP6-ping from outside to prefix::1 was ok, etc.

Hope that's helpful.

https://community.plus.net/t5/IPv6-Trial/IPv6-Trial-Update/m-p/2006979#M3450 was where I first wrote about this.

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You should get a DHCP reply from PlusNet.  I configured the DHCP client on my router (a Mikrotik HAP AX3 router) just to ask for prefix delegation, not ask for an address, use as the default route and to use peer for DNS and the PlusNet server duly responded with the prefix, and DNS server.  As it is a PPPoE link it really only needs the link local addresses for the two ends of the PPPoE connection to work correctly.

I did want an IP address I could access the router with from the internet, solely for the point of implementing a Thinkbroadband quality monitor, but I just used the address I had assigned to the internal LAN bridge interface of the router and that works fine.

[#8]

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@wmh wrote:

@dave ,

Is there a way I can troublehoot the PlusNet IPv6 connection?  
...

Will.

---

Is there anyway that the Juniper router can apply a packet trace to the PPPoE connection?  I did this with my router and asked it to capture DHCPv6 packets crossing that interface.  When the interface comes up you should at least see a DHCP request and reply for the Prefix delegation occur - after that the IPv6 traffic should just "work".

[#9]

"You should get a DHCP reply from PlusNet.  I configured the DHCP client on my router (a Mikrotik HAP AX3 router) just to ask for prefix delegation, not ask for an address, use as the default route and to use peer for DNS and the PlusNet server duly responded with the prefix, and DNS server.  As it is a PPPoE link it really only needs the link local addresses for the two ends of the PPPoE connection to work correctly."

OK, good.  Sounds like my understanding was not too far off then.  I indeed have the prefix but I suspect the DNS server is being lost somewhere.  And the PPPoE link was working exactly as you describe (well, I believe it was) for 2 weeks but has now gone dead for IPv6.  And internal LAN bridge is what I believe I am seeing it use; thats working for you, so I am probably looking at a UniFi firewall bug.

I am going to try two things later.  1. Factory reset the Unifi device too see if I get the IPv6 back, and if that fails, 2) inspired by @MPC 's above Debian router idea, will look at hooking up an old laptop to troubleshoot the PPPoE directly and at least eliminate that.

Thanks for the help

[#10]

"Is there anyway that the Juniper router can apply a packet trace to the PPPoE connection?  I did this with my router and asked it to capture DHCPv6 packets crossing that interface.  When the interface comes up you should at least see a DHCP request and reply for the Prefix delegation occur - after that the IPv6 traffic should just "work"."

Probably.  But I definitely get DHCPv6 and a delegation.  I can see my delegation inside the Juniper on the pp0.0 interface.  Its just not coping properly with the IPv6 I think.  Or I havent configured it correctly, which is also quite possible.  Which seems strange; I have been using it fine with a HE tunnel for years now.  But the Juniper is definitely missing bits of commands that are apparently available on newer firmwares. 

[#11]

Sorry I could have been clearer - when just asking for an address via dhcp6, I got no reply.

When asking for PD, I get a valid response.

It took me a while of checking and rechecking basic dhcp6 to give up before trying just the PD request.

And also to note this was back at the start of the trial and I haven't rechecked recently.