subnet prefix length > 64 breaks IPv6?

sthaug at sthaug at
Sun Dec 25 10:26:08 UTC 2011

> > prefixes on the same link.  Choosing to make use of a 120-bit prefix
> > (for example) will do nothing to protect against a rogue RA announcing
> > its own 64-bit prefix with the A flag set.
> >
> I could not find any "A flag" in the RA. Am i missing something?

It's part of the Prefix Information option. See

Steinar Haug, Nethelp consulting, sthaug at

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