Citeren Steven Barth <cy...@openwrt.org>:

After thinking it through a bit more, I changed the default behavior to the following: The preferred lifetime is now as given by the ISP, however the DHCPv6 server will only hand out the address with the highest preferred lifetime (= the ULA unless disabled).

Since I avoid ULA like the plague, this probably won't be a problem for me and global IPv6 addresses will be served. But I'm not convinced that favoring a ULA prefix (if available) over an ip6prefix is best at all times.

Thus flash renumbering should still work (since only the ULA-address cannot be changed immediately).

Is that okay with you or do you see any other issues?

Well, one thing that still worries me, is that the behavior of the DHCPv6 server is different depending on the state of the O flag. From a DHCPv6 client perspective, it shouldn't. When both M- and O-flag are set, it is up to the client to decide if it wants to use DHCPv6 or SLAAC. You've made it clear that there may be reasons not to use an adress provided by DHCPv6 and use SLAAC instead. But this should not be the only (or default) way of operation. There may be reasons other than broken IPv6 uplinks why network administrators choose to set both M- and O-flags. I think the other reasons are far more common (the lack of DHCPv6 support in Android is just one of them). Even with the changes pushed out today, odhcpd makes the assumption that the ip6prefix can't be relied upon if a ULA prefix is provided and I think that is just incorrect.

Arjen
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