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by jeroenhd 862 days ago
With how weirdly complicated Azure was about IPv6 last time I looked into it, I wouldn't be surprised if it'd be more complicated than on AWS.

I'm not convinced it ever improved. Looking up a quick guide brings up https://learn.microsoft.com/en-us/azure/virtual-network/ip-s... which tells you to just... assign a random network from 2404:f800::? What even is this network? Are they using a routable IPv6 address as a substitute for an ULA for their NAT'ing load balancers? Why 2404:f800:8000:122::/64 specifically?
1 comments
WirelessGigabit 861 days ago
Microsoft owns 2404:f800::/30.

I just did the tutorial and I noticed that in the Azure portal it shows a public IPv6 address and a private IPv6 address. From my machine I connect to the public one and magically end up on the private one.

Curling what is my ip6 from the machine yield the public IPv6 address.

I suppose all of this is needed to ensure LB can be done? And it's easier to do with a range like this than a ULA which by default isn't routable.

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jeroenhd 861 days ago
They do, but they tell you to use a specific /64, which confuses me. I would've expected them to say something like "the address starting with 2404:f800 in your dashboard".

The "private" IPv6 address can be a ULA without any issues if the network is designed to be fully NAT'ed (i.e. for load balancing, maybe failover I guess). If you're not using the global address on your local machine and translate the public address into a private one, your local network doesn't need to have a routable IP address.

I suppose it works just as well, but it makes using IPv6 more confusing for now reason. It's as if Microsoft decide to use 20.64.0.0/10 for private networking on Azure, which they can do (they own that space after all, they can decide not to use it), but just doesn't make much sense.

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