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I know this is not an expected scenario, but it occured while testing some IPv6 features:

  • I started by deleting an existing SLAAC addres on my eth0 interface.

  • Then I manually deleted the LLA address of my eth0 interface. (ip addr del dev eth0)

  • After a while (few minutes), the eth0 interface configured a new SLAAC address

The way I understand this is that my host received an RA message telling it to do SLAAC, although it had no LLA address at the time.

I'm thinking that maybe this is possible in the case that my router sends the RA to all hosts on the network (ff02::1), and my host is still able to listen to that multicast group, even without the LLA.

Could you confirm whether my analysis sounds reasonable?

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  • Why do you think the host would ignore NDP via multicast when it has no link-local address?
    – Zac67
    Commented Jun 6 at 15:03
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    A LLA is required per spec. A compliant stack will setup a LLA as soon as the link is enabled. Yes, it can be erased, but for IPv6 to function properly it MUST have a LLA. Of course, there are plenty of people who don't understand this, and/or explicitly ignore it.
    – Ricky
    Commented Jun 6 at 19:11
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    Yes, you can listen to multicast with any address, including no address.
    – Ricky
    Commented Jun 6 at 19:12
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    The destination address is the multicast group, not the link-local address. Your host will still listen to the multicast groups to which it is subscribed.
    – Ron Maupin
    Commented Jun 7 at 13:51

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