On Tue, Feb 12, 2013 at 6:48 PM, Brian Haley <[email protected]> wrote: > On 02/12/2013 05:43 PM, Sheng Yang wrote: >> I am also a little dubious here, but if people want to get some >> smaller subnet, do they able to get it anyway on IPv6? > > You typically use a /64 on a link, but you can use longer. The problem is > that > address auto-configuration will only work if the prefix length is 64 since > that > plus the IID length of 64 == 128. In your case, 96 + 64 is simply too large. > > A Linux system receiving a !64 prefix length will log this error in > /var/log/kern.log: > > IPv6 addrconf: prefix with wrong length 96 > > That would confirm my assumption.
The auto generated link local would be always /64, but seems irrelevant here. We didn't use autoconf here, because we need to know the IP we assigned from dhcp server. So lost autoconf ability seems fine to me. I just don't know if it's legal even when we use stateful dhcpv6 to assign IPs. --Sheng > > -Brian > >> On Tue, Feb 12, 2013 at 1:06 PM, Brian Haley <[email protected]> wrote: >>> On 02/08/2013 09:59 PM, Sheng Yang wrote: >>>> Hi Simon, >>>> >>>> I found I can't assign IPv6 address for /96 subnet. >>>> >>>> I specified DHCP range use 96 bits prefixes: >>>> >>>> dhcp-range=fc00:3:1602::7473,96,static >>> >>> This is in violation of RFC 4862 Section 5.5.3 Item d, right? >>> >>> "If the sum of the prefix length and interface identifier length >>> does not equal 128 bits, the Prefix Information option MUST be >>> ignored." >>> >>> Basically, anything besides a /64 on an Ethernet isn't going to work. >>> >>> Unless I mis-understood the question? >>> >>> -Brian >> > _______________________________________________ Dnsmasq-discuss mailing list [email protected] http://lists.thekelleys.org.uk/mailman/listinfo/dnsmasq-discuss
