[dns-operations] Link-local IP addresses for a resolver?

Paul Ebersman list-dns-operations at dragon.net
Wed Sep 25 00:53:28 UTC 2019

marka> When a *ISP* advertises a DNS server to its *customers* IT SHOULD

That doesn't mean it can't be ULA. And it would be hideous but you can
use LL if you flatten the broadcast domain. There are lots of reasons
why this isn't the best idea but you don't know everyone's network, so
saying "that's bad and I'd never do it so we shouldn't support it" at
the network layer isn't a reasonable answer.

marka> The CPE is a SITE boundary.  It is also a Link-Local
marka> Boundary. ULA source packets DO NOT cross the CPE by default it
marka> the CPE is properly configured.  Link-Local packets should NEVER
marka> cross the CPE as it is NOT A BRIDGE/SWITCH but is a router.

No need to shout... And the same could be said of RFC 1918 but ISPs have
used that for thousands of homes, crossing thousands of CPEs. Not the
best choice and not your choice but it does work for some folks.

"site boundary" and what is "local" in ULA have never been well defined
because of this.

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