WRT "Anycast DNS"; Perhaps a special-case of ULA, FD00::53?
You want to allow for more than one for obvious fault isolation and
load balancing reasons. The draft suggested using <prefix>:FFFF::1 I
personally would suggest getting a well known ULA-C allocation
assigned to IANA, then use <prefix>::<protocol assignment>:1
<prefix>::<protocol assignment>:2 and <prefix>::<protocol
assignment>:3, where <protocol assignment> could be "0035" for DNS,
and "007b" for NTP, and if you're feeling adventurous you could use
"0019" for outgoing SMTP relay.
I thought ULA-C was dead... Did someone resurrect this unfortunate bad
idea?
I'm not sure, I've not checked for a pulse recently. Last I looked it
seemed that there was ULA-L and ULA-C, and most people were saying use
ULA-L unless you needed ULA-C, ULA-C seemed like a good fit for this, if
it's been buried then sure ULA-L would fit the bill just as well.
Easily identified, not globally routable, can be pre-programmed in
implementations/applications ... ?
Exactly, seems easy, straight forward, robust, reliable and allows
for things like fate sharing and fail over.
Why pull this out of ULA? Why not pull it out of 0000/16 or one of
the other reserved prefixes?
With my proposal above it only requires a /96, seems silly to use up an
entire /16 on a /96 worth of bits. It shouldn't come out of 2000::/3
because that's globally routable and this is defined to sit within
locally scoped addressing.
I have no major thoughts either way as to exactly where the range comes
from other than it should be an easy to spot, and easy to type range
which suggests plenty of 0's :)
