AWS Elastic IP architecture

tvest tvest at
Sun May 31 12:26:57 UTC 2015

Point of clarification: AWS customer IP subnets can overlap, but customer VPCs  that encompass overlapping subnets cannot peer with each other. In other words, the standard arguments in favor of address uniqueness still apply.


On May 31, 2015 7:23:37 AM EDT, Andras Toth <diosbejgli at> wrote:
>Congratulations for missing the point Matt, when I sent my email
>(which by the way went for moderation) there wasn't a discussion about
>Classic vs VPC yet. The discussion was "no ipv6 in AWS" which is not
>true as I mentioned in my previous email. I did not state it works
>everywhere, but it does work.
>In fact as Owen mentioned the following, I assumed he is talking about
>Classic because this statement is only true there. In VPC you can
>define your own IP subnets and it can overlap with other customers, so
>basically everyone can have their own for example.
>"They are known to be running multiple copies of RFC-1918 in disparate
>localities already. In terms of scale, modulo the nightmare that must
>make of their management network and the fragility of what happens
>when company A in datacenter A wants to talk to company A in
>datacenter B and they both have the same 10-NET addresses"
>On Sun, May 31, 2015 at 7:18 PM, Matt Palmer <mpalmer at>
>> On Sun, May 31, 2015 at 01:38:05AM +1000, Andras Toth wrote:
>>> Perhaps if that energy which was spent on raging, instead was spent
>>> a Google search, then all those words would've been unnecessary.
>>> Official documentation:
>> Congratulations, you've managed to find exactly the same info as Owen
>> already covered:
>> "Load balancers in a VPC support IPv4 addresses only."
>> and
>> "Load balancers in EC2-Classic support both IPv4 and IPv6 addresses."
>> - Matt

Sent from my Android device with K-9 Mail. Please excuse my brevity.

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