People who advocate for IPv6 are always like 'ahhhh just plug it in and its ready to go!!!' There's even twitter accounts that shame people for how they approach IPv6. But after doing a crap load of network programming I can tell you its really not simple at all.
- IPv6 has many different address types.
- Depending on the type you want to bind to it needs to be handled different.
- Some types need an interface ID appended to them.
- This is conditional on the type of the OS.
- Windows has no easy way to get the ID programmatically.
- Some address types need additional bind info like the 'scope id.'
- Whether you can reach a specific addr type in a con depend on the addr you bind to.
- IPv6 was designed to have plenty of addresses so that NAT isn't needed. Guess what: IPv6 can still do NAT like NAT6. In which case you won't have any nice global scope addresses to bind to.
Writing good network code depends on being able to list the interfaces on a machine and the addresses that they have. With IPv6 this is desirable since it lets you know if you have any global scope addresses, what your local-scope addresses are, and other kinds. But from what I've seen seen most programming languages fall back to using default routes for everything. This means that the programmer literally can't lookup the addresses and interfaces for their software.
Also lastly: getting a modern router that properly supports IPv6 isn't easy at all. I literally have a cupboard filled with PoS routers that can't do IPv6 properly. Everything that Telstra and Optus tend to give customers; most Dovado routers; GL inet routers (can do NAT6 but who wants that); 'netgear nighthawk' (I found a security vuln in netgears router when testing v6); and so on. People will say 'just slap Open-wrt on something and call it a day.' But these are the kinds of people who will spend 120+ hours reading the open-wrt wiki and learning electronic basics to setup a custom router. What they think is 'easy' doesn't take into account all the time they've already spent learning such niche BS. I have better things to do than (((just waste 1 billion hours with open-wrt and end up with someone that still doesn't work.)))
Your "end-user routers suck ass" comment is totally true. I wish the end-user and SOHO networking gear market wasn't a fucking race to the bottom.
Your other comments simply aren't a substantial concern at end-user sites in the real world.
* The only scopes that end-user sites might care about are global and link-local. I expect that situation is the same at nearly all non-end-user sites. Reading through the RFCs, it looks like the other scopes are ONLY relevant in multicast [0][1]... and even then, anything other than interface-local, link-local, and global looks like it's programmed into the routers and switches of the network, rather than host computers themselves.
* If you have functional IPv6 service at your site, your application software cares as much about the interface's fe80::/10 link-local address as it does about the 169.254.0.0/16 link-local address... that is, not at all. The rule is simple: "If you want to talk globally, use an interface with a global address. If there's no global address, send it to the 'default' router and hope for the best.". It's actually a better situation than in IPv4 where you pretty much never have a globally-connected address.
* Yes, you can do IPv6 NAT. In that case, you're no worse off than in the usual end-user IPv4 deployment. The cool thing about IPv6 is not that NAT doesn't exist, it's that there's far, far more than enough address space to make it so that you don't HAVE to deploy NAT at end-user sites. That doesn't mean that it's impossible for stupid, frightened, currently-ignorant, or revenue-maximizing ISPs to deploy NAT.
scopes are deprecated and link-local is only a thing so that the network can bootstrap itself. if you’re deploying ipv6 all you care about are global and ula, which are scope-less
My GL inet router does native IPv6 just fine, without needing NAT6 or anything. Within its interface you can turn it on as "native" and it all just works.
- IPv6 has many different address types.
- Depending on the type you want to bind to it needs to be handled different.
- Some types need an interface ID appended to them.
- This is conditional on the type of the OS.
- Windows has no easy way to get the ID programmatically.
- Some address types need additional bind info like the 'scope id.'
- Whether you can reach a specific addr type in a con depend on the addr you bind to.
- IPv6 was designed to have plenty of addresses so that NAT isn't needed. Guess what: IPv6 can still do NAT like NAT6. In which case you won't have any nice global scope addresses to bind to.
Writing good network code depends on being able to list the interfaces on a machine and the addresses that they have. With IPv6 this is desirable since it lets you know if you have any global scope addresses, what your local-scope addresses are, and other kinds. But from what I've seen seen most programming languages fall back to using default routes for everything. This means that the programmer literally can't lookup the addresses and interfaces for their software.
Also lastly: getting a modern router that properly supports IPv6 isn't easy at all. I literally have a cupboard filled with PoS routers that can't do IPv6 properly. Everything that Telstra and Optus tend to give customers; most Dovado routers; GL inet routers (can do NAT6 but who wants that); 'netgear nighthawk' (I found a security vuln in netgears router when testing v6); and so on. People will say 'just slap Open-wrt on something and call it a day.' But these are the kinds of people who will spend 120+ hours reading the open-wrt wiki and learning electronic basics to setup a custom router. What they think is 'easy' doesn't take into account all the time they've already spent learning such niche BS. I have better things to do than (((just waste 1 billion hours with open-wrt and end up with someone that still doesn't work.)))
'IPv6 is easy. It just works.'