On 17/03/18 15:36, Brian E Carpenter wrote: > On 17/03/2018 13:44, Richard Hector wrote: >> Hi all, >> >> Apologies if this is a bit off-topic, but I know there's lots of IPv6 >> knowledge here :-) >> >> If I have an IPv6 ULA block (or several) > > Why mention ULAs? Your question applies equally to normal (globally > routeable, GUA) > addresses. ULA and GUA prefixes are treated exactly the same both in SLAAC > and in > DHCPv6.
Fair call - I had more or less assumed that, and was contemplating doing the same thing for the GUA addresses assigned by Vodafone (FibreX) - except that prefix is dynamic. But I know my knowledge is incomplete, and the general rule of asking questions on lists is to provide whatever info might be useful. >> using SLAAC, and I want to >> additionally give out some static addresses in one or more of those >> blocks, am I right in thinking I can pick anything I like as long as it >> doesn't have the magic fffe in the middle? > > As far as I can see you can pick any valid /128 address in the applicable > /64 prefix. The probability of a clash with a SLAAC-generated address > is minimal, and duplicate address detection works. > > I don't see where :fffe: comes in any more, we dropped the model of > making up the interface identifier from the MAC address long ago. > Modern operating systems just use a pseudo-random 64 bits. Generally > people seem to use small integer identifiers for servers. > smtp.gmail.com is 2404:6800:4008:c00::6c for example. Ok - I clearly need a better source of current IPv6 info than arbitrary web search results :-) Any tips? Hmm, perhaps https://www.apnic.net/community/ipv6-program/ipv6-bcp/ is a good start. I notice that all my addresses do have fffe in them though, and at a quick glance are based on the MAC address (Linux - debian stretch). Maybe there's a feature I need to enable. net.ipv6.conf.eth0.use_tempaddr looks like it; presumably it won't argue with my static allocations. What happens with the duplicate address detection? The SLAAC one tries again, and my static one stays put? >> Is there a more formal approach? Is this (SLAAC plus statics where >> required) the normal way of doing things? > > I think so, except for True Believers in DHCPv6, or people who pay good > money for APAM software. Great, thanks a lot :-) Richard _______________________________________________ NZNOG mailing list NZNOG@list.waikato.ac.nz https://list.waikato.ac.nz/mailman/listinfo/nznog
