The time has come to talk about something uncomfortable to a lot of you. You’ve been using legacy methods for far too long. It’s time to move to IPv6.
But, of course, there’s a lot more to IPv6 than ‘just’ switching everything over. A lot of systems in the world still haven’t adopted it after nearly 25 years, and although software support is virtually a requirement these days, that doesn’t mean it’s widely enabled. There are also still a lot of misconceptions from network administrators who are scared of or don’t properly understand IPv6, and I want to address all of that.
But, for me to describe to you the best setup for your networks going forward, I need to understand for myself how all of the IPv6 transition mechanisms and behaviors work. To understand where transition mechanisms fail, I’m spending a fully week with only IPv6 and reporting on what works and doesn’t.
At the start of this, I’d like to absolutely stress that the NAT you know and hate was not imagined when the Internet Protocol was created, and in many ways has introduced a huge amount of headache in routing. You should stop thinking of NAT as a security mechanism and think of it as the emergency address exhaustion prevention that it is. Likewise, CG-NAT is a dire emergency address exhaustion prevention mechnism that nobody really wants to deploy unless they absolutely must. Don’t blame your provider when they deploy CG-NAT, embrace IPv6 and global routing instead.
Crash Course on IPv6⌗
The biggest hurdle to implementing IPv6 on your own isn’t usually ISP support, router support, or client support. It’s the mental thought process behind un-learning the legacy methods of network design. With IPv6, we aren’t just copying the mistakes of IPv4 and adding a wider address space, we’re going back to how the internet protocol was intended to behave before we started running out of addresses, getting rid of network address translation, and generally adding a stronger focus on proper subnet design and routing.
So, here are a few quick notes that can are crucial in understanding IPv6:
Addresses are 128 bits long and written as 8 four-letter hex blocks separated by colons (i.e. fd69:beef:cafe:feed:face:6969:0420:0001 )
) Leading zeros can be omitted (i.e. 0420 can become 420 , but not 42 )
can become , but not ) Groups of zeros can be omitted with two colons, but only once in an address (i.e. 2000:1::1 , but not 2000::1::1 as that is ambiguous)
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