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Acronyms, initialisms, abbreviations, contractions, and other phrases which expand to something larger, that I’ve seen in this thread:
Fewer Letters More Letters CGNAT Carrier-Grade NAT DNS Domain Name Service/System IP Internet Protocol IoT Internet of Things for device controllers NAT Network Address Translation VPN Virtual Private Network VPS Virtual Private Server (opposed to shared hosting)
7 acronyms in this thread; the most compressed thread commented on today has 13 acronyms.
[Thread #814 for this sub, first seen 18th Jun 2024, 11:05] [FAQ] [Full list] [Contact] [Source code]
Very useful, but I don’t understand concept 1, “Don’t pick numbers”.
If I’m right, it’s basically saying don’t do stuff manually, just let the computer do it. I kind of disagree with this. All of my fixed devices have a fixed IP that I manually assigned and derived from the original v4 schema I also have. For example 192.168.x.y becomes prefix::y
Am I misunderstanding something?
This is an old post about ipv6, but it inspired me to go looking, and I wanted to share my findings.
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for globally routeable IPv6 addresses, probably do let it happen automatically, either direct from the ISP, through the router by prefix delegation, or your own implementation of prefix delegation.
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for devices you want to access, internally, create a ULA within the fd00::/8 space, and assign numbers (and names) however you like. Translate all your 192.168.x.y IPv4 addresses to fd00::x:y and go. Only limitation is you won’t be able to access those devices, using the ULA, from outside your network.
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you can do both of these on the same subnet, and devices pick up both addresses then use the global address for internet and the ULA for intranet.
That means you can do dhcp, dynamic DNS, private domains, and all the stuff you know about IPv4 for IPv6, and still do all the stateless autoconfig that “they” want. Some devices, like my android phone, never played well with dhcpd6, but immediately preferred IPv6 as soon as I let them SLAAC.
If the prefix assigned by the ISP doesn’t change, then device SLAAC address shouldn’t change, either, because they’re calculated from MAC, so if you need to access some internal devices from the internet, you have to mark that address, but (IMO) marking the full address is not that much worse than marking the prefix and remembering the device number.
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Ipv6 requires fundamental rethinking about how addressing is done. If you’re trying to apply v4 concepts to V6 you likely end up running into something they intentionally designed out.
A unique local address is an address space where you could do that. It’s the equivalent to RFC1918 eg. 172/192/10. So you could statically assign fd0::x, and that is expected, but not required generally.
I wouldn’t give each device a static unique global address unless they need to be accessed via wan without domain consistently. You lose device privacy really quickly that way because every device gets a unique globally routable address. It’s fine for internet facing services but most Linux, Windows, and mobile implementations are using ipv6 privacy extensions by default to ensure you get a random GUA every day.
My network is dual stack and I connect mostly over ipv6 to all my internal clients using internal DNS. If my internal DNS is ever down I can fall back to ipv4 or it’s basically the one box on my network with an easy to remember ULA.
On one hand you definitely don’t want to be assigning manual/static IPv6 to all your devices because if your prefix ever changes you’ll have to update it everywhere. IPv6 doesn’t really have a concept of private address space (with a few exceptions).
On the other hand most modern IPv6 stacks support dynamic protocols like SLAAC while also assigning a static suffix to the published prefix (e.g. You want :0:0:1234:1 to go to your server, and SLAAC gets the prefix 200x::5678/64 your server would assign itself 200x::5678:0:0:1234:1).DHCPv6 fixes a lot of these headaches for managed networks by allowing you to reserve specific IPv6 for a given DUID.
IMO, your network, do what you want.
I have two jump Raspberry PIs that I have static suffixes so I always know where they are without relying on DNS or whatever.Edit: I apparently misremembered how I had these setup. I use a custom interface up script to take the SLAAC prefix and append the custom suffix to it as a secondary IP.if your prefix ever changes you’ll have to update it everywhere
I mean that’s a good point but I’m paying money to not have my prefix changed. If I were to do it the intended way using DNS, how would I set up the DNS to be prefix agnostic? How would I reference devices in the firewall?
Its a bit complicated and depends on your ISPs support level.
If your ISP supports basic IPv6 they will likely use SLAAC or DHCPv6 to advertise the /64 that any directly connected devices, like your router, can use (/64 being the default size for a single LAN segment, even between point-to-point connections). If you have devices behind that router that want to use IPv6, you will need additional prefixes. The most common method nowadays is to use Prefix Delegation (DHCPv6-PD) where your router will ask the upstream router for an additional routeable prefix which you will use on another interface of the router. The RFC for prefix delegation recommends a /48, but many ISPs are not delegating that much. I only get half of a /60 from my ISP’s modem.
If the ISP just provides you a static routeable prefix, then you would just assign that to your router’s interface and enable SLAAC/DHCPv6 to give out that prefix. This would only need to be configured in a single device and is why they don’t recommend hard coding servers and workstations with IPV6 addresses.
Keep in mind that your router will also need a firewall as all of these IPv6 prefixes are routeable and public. While IPV6 space is quite like finding a needle in a haystack, you could still find yourself having a bad day if you treat it like private IPV4 space.
The end result though is that you would setup DNS so that devices register their IPv6 addresses and it just works. There’s also the MDNS protocol that supports IPv6 which will do segment-local resolution for device names.
I think there’s some misunderstanding
I get how IPv6 works, I got a /48 from my ISP. The problem is that I have some 15 devices here that I have to refer to in DNS and either I have to change their static IPs or I have to change their IPs in DNS if the prefix ever changes (it shouldn’t, because I pay for them to not do that). My laptop, phone and desktop do not get a static IPv6 and use the privacy extension. Is that not how you’re supposed to do it?
Not sure if you know privacy extension is mostly for outbound traffic. When you go to a website it well use privacy ipv6. Can still use management ipv6 for local connections. For max privacy every device should have it enabled as there are ways to trace if some devices do not have it enabled on your network.
I don’t think you understand. I know privacy extension is for outbound and not inbound, but what use is it on a server?
From reading one device can ruin the privacy extension use. Don’t know if a server would be they bad since it isn’t going to sites.
