Comment by yosamino
6 hours ago
They probably mean that when using SLAAC - I guess the easiest way to get ipv6 connectivity - there is no equivalent to the way you can update DNS the way it would work with DHCPv4 or DHCPv6.
You pointed out one way - justuse DHCPv6, but that looses some of nice SLAAC properties.
A different way is to run mdns and let the devices announce their own hostnames.local.
Different tradeoffs, but in practice not too difficult to get to work.
I guess one could even do both...
> They probably mean that when using SLAAC...
If that's the case, then you've got to think of SLAAC as operating exactly like IPv4 address autoconfiguration (sometimes called "IPv4LL")... except that you usually get globally-routable IP addresses out of it.
If you want the management niceties that you often get when using DHCP, then you have to use DHCP.
Some very loud purists might say "SLAAC is the only way to use IPv6!". I completely ignore the convenience of LAN-side prefix delegation and say two things:
1) "Good luck with telling your IPv6 clients about things like your preferred NTP server."
2) "For ages, Router Advertisements have had entirely independent 'autoconfigure your addresses', 'use stateful configuration for your "other" configuration' [0], and 'use stateful configuration for your addresses' bits. It's legal to have any number of them enabled. This is a deliberate choice by the folks defining IPv6."
In general, the folks who scream about how IPv6 NAT and DHCPv6 should not exist and should never be used should be ignored... at least about that topic.
[0] Things like NTP and DNS that other good stuff that DHCP can be used to tell hosts about.
I mostly meant that DHCPv6 was an afterthought, and was complaining about the length of IPv6 addresses when they are truly random/EUI64. As a network guy who has had to write down or quickly type IP addresses down for troubleshooting thousands of times, v4 is much easier for humans to work with than a full v6.
(Oh and Android doesn't support DHCPv6 at all, but that doesn't matter much for server environments/DNS reachability).
In hindsight of EUI64 being shunned in favor of privacy addresses, plus how much of the IPv6 space is reserved for future use, I wonder if IPv6 could have achieved all of its goals with a 64 or 80 bit address instead of 128.