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Comment by everdrive | Hacker News Reader

If IPv6 were just an improved header and a longer address I'd be perfectly happy with it. I wasn't discussing either point you raised.

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That is literally all it is. There is nothing else to it. You get P2P connections and a longer address. The rest is what they removed from the protocol, not what was added.

SLAAC is a huge and complex part of IPv6. Higher reliance on ICMPv6 is also a big part of it. Networking stacks for IPv6 are also more complex, especially if you want to support SLAAC, requiring things like multiple IPs on every machine by default, and so on. The very fact that you have to choose between static IP, SLAAC, and DHCPv6 is another complication - if the choice is even there, as some major devices don't support DHCPv6 (Android).

> SLAAC is a huge and complex part of IPv6.

Complex? Could you elaborate what exactly is complex about SLAAC? Are you referring to the various address generation modes?

SLAAC is stupid simple. The router just sends out its address, the netmask and optionally DNS servers. You can configure each host on your network to use the MAC address based suffix, a privacy one (random and changes several times an hour), or a static suffix. This is way simpler than DHCP which is stateful and requires multiple back and forths with the DHCP server.

And yes each host/interface can have more than one address which is amazing compared to having to create virtual interfaces for IPv4. You can literally just add more addresses.

Oh and when working with Docker or other container systems you can just use a link-local subnet instead of setting up a virtual network which makes things so much easier and nicer. There it really is zero configuration, not even firewall rules. It takes less effort to do this than to use IPv4.

SLAAC doesn't exist with IPv4. If you want SLAAC, you have to run v6. Nobody forces you to use SLAAC. It's not an argument against the use of v6.

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