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IT Pros Blast Google Over Android's Refusal To Play Nice With IPv6
alphadogg writes: The widespread popularity of Android devices and the general move to IPv6 has put some businesses in a tough position, thanks to Android's lack of support for a central component in the newer standard. DHCPv6 is an outgrowth of the DHCP protocol used in the older IPv4 standard – it's an acronym for 'dynamic host configuration protocol,' and is a key building block of network management. Nevertheless, Google's wildly popular Android devices – which accounted for 78% of all smartphones shipped worldwide in the first quarter of this year – don't support DHCPv6 for address assignment.
Google's IPv6 support for mail is what annoys me. I have a static non-tunneled IPv6 address for my server, have reverse DNS set up for it that resolves properly, have SPF and DKIM records set up properly, and they still refuse to accept mail from the server, even though they accept my IPv4 mail just fine. Lots of other folks have been having the same problem, and it really makes me wonder why Google's even bothering with IPv6 SMTP when they're refusing mail from so many legitimate (i.e. non-spam) hosts.
Spoken like someone who's never managed a deployment that's bigger that can fit in one's basement - Something a lot of the v6 creators I think have in common.
DHCP v6 exists not to coddle or comfort admins used to a v4 world. DHCP v6 was added because v6 will /Never/ be adopted without it. Ever. Full stop.
DHCP facilitates two-way communication prior to address assignment and lends flexibility to deployments that are now considered indispensable. It lets clients tell the network about themselves so they can be assigned the corrects settings (And not just an address!)
It's shit like this that keeps v6 from being adopted. (We should have been there a decade ago) Proselytizing form old, out of touch "experts" (With four digit slashdot IDs no less) with a vision for how networks work that didn't work, and is no longer relevant either.
I work for a (smallish) ISP so let me tell you why you will simply not get any IPv6 service without DHCPv6 on our network.
It has nothing at all to do with being IPv4 old-timers. That is just you not understanding the complexity of the world out there. Our network was build from the start with the idea that IPv6 is the future.
We use DHCPv6 to provide every user with his own /48 prefix. Yes you said that DHCPv6 is a great solution for prefixes. But we also use it to deliver a /128 to go with that prefix. We need this to have a stable and predictable address that we can use as next hob for your shiny new prefix.
We had this very same debate on the NANOG mailing list. Some people there asked why does your routers not sniff the DHCPv6 packet and add the route dynamically? Two reasons. One, that is not in any standard, so our vendor did not implement it. Two, it does not work if you have router redundancy (how would the backup router know the route?).
There are more reasons an ISP would not want to use SLAAC. It exposes 2**64 addresses to the ISP network access routers. This can harm the network in many different ways and you simply do not want your ND caches to be full of that crap. You want to use as few slots in the shared ND cache per user. Therefore you are going to disable SLAAC on the customer edge and use some other mechanism. One guy suggested not using GUA on the customer links and only use link local addressing here. We choose to use /128 DHCPv6 assigned addresses. In either case, GUA-SLAAC is a fail in the provider network.
SLAAC is great inside the household of our customers. But we leave that decision to the customer and his choice of CPE-router.
The problem with Android is that it should really be able to act like a CPE for tethering purposes. Therefore is should be able to accept our CPE configuration. Android should also be able to ask for a prefix to be sub-delegated from the house CPE and it should accept that this might come with extra addresses that will be used for routing or for other purposes.