Static IPv6 - doing my head in :-/

IDNet provide me with a /48 address that is supposed to be static. I thought that meant that all but the last 12 hex digits would be fixed. Instead I'm seeing this as the first few digits:

Up until Sunday morning: 2a02:0390:feed:6c03:
As from Sunday morning: 2a02:0390:6c03:0:

The last 12 digits are fixed because it's a server and I've disabled the Windows auto generation feature.

Got a reply from IDNet support that confused me further

"On authentication your router gets an IPv4 address and the /64. Once authenticated the router then issues a DHCP6 request to get the /48. Both the /64 and /48 are static blocks to your account, it is up to your router how these are then assigned and whether the router decides to use the 2A02:390:FEED:6C03 address or one from the /48 range."

I do not use DHCP6 at all on my setup, and things are working fine. I suspect this is because they have statically routed the /48 to my connection, which means I do not need to "request" it using DHCP6. If you can contact them to enable this, I would do so, as it can simply things. Depends on your requirements though.

Per what they've already said, the FEED prefix is the /64. A random address from that gets assigned to the WAN side of the router. You then assign a static /64 from the /48 prefix to your LAN side (2A02:390:xxxx:0:... most likely). I also configure an additional static address from the /64 on the WAN side for BQM monitoring (I'm able to do this as my setup is Linux, not an off the shelf router).

The only thing I have done to make sure this all works is to allow routing advertisements to be accepted on my ppp interface. Everything else then falls into place without the need for DHCP6 on the WAN side.

So - does that mean that it's correct to say that '2a02:0390:6c03' is my 'static IPv6 address' (though of course it's only a prefix)?

And I need to go to the LAN configuration page and specify that plus some 'xxxx' of my choosing and prefix length of 48 there so that it stays the way it is. That way the router WAN address may change (which I don't care about) but my server address will be fixed.

Edited by Andrue (Tue 13-Jun-17 11:31:58)

In reply to a post by Andrue:

So - does that mean that it's correct to say that '2a02:0390:6c03' is my 'static IPv6 address' (though of course it's only a prefix)?

It's your static IPv6 /48 prefix, rather than address, yes. It's up to you (and your router) how you make use of the address space under it. Most times, the DHCP6 on your router (and router advertisements from it) in conjunction with your LAN devices will result in them auto-configuring themselves with different (dynamic) IPv6 addresses under this static /48 prefix over time.

In reply to a post by Andrue:

And I need to go to the LAN configuration page and specify that plus some 'xxxx' of my choosing and prefix length of 48 there so that it stays the way it is. That way the router WAN address may change (which I don't care about) but my server address will be fixed.

Yes, sounds about right. LAN settings should not involve the FEED prefix at all, only the /48 prefix. If you need to specify anything, just use the first available /64 of the /48, which will be 2a02:390:xxxx:0::/64 (where xxxx is unique to your connection). Note you can shorten this to just 2a02:390:xxxx::/64 (removing the 0) under existing IPv6 notation, which is why it's handy to just use this very first /64 of the /48.

Thank you very much for you help and explanation. It's not easy to find this stuff on the web.

And in case anyone finds this thread when searching it's worth noting that the 8800NL R2 requires that when configuring the LAN you specify the interface address and prefix which means:

aaaa:bbbb:cccc:dddd:eeee:ffff:gggg:hhhh/48

Although everything from dddd onward is arbitrary. I went for all zeroes. And note that as the text at the top of the page says you can't compress the address.