[Pkg-utopia-maintainers] Bug#898527: libnss-mdns: Adding ipv6 scope id breaks NFS mounts

[Ross Vandegrift]

On Mon, May 14, 2018 at 01:38:15PM +0100, Simon McVittie wrote:
> Not including the scope ID in the result of address resolution breaks IPv6
> link-local addressing (fe80:*), and link-local addressing and mDNS are both
> parts of the Zeroconf stack, so they (should) go well together.

Yep, this makes perfect sense - the scope id shouldn't go away entirely.

> Or possibly nss-mdns should be setting the scope ID to the interface
> index for link-local addresses, but not for other addresses? It isn't
> entirely clear to me what nss-mdns is meant to be doing here.

On one hand, rfc4007 11.1 says that the scope id should not be used for
global scope, loopback, and undefined addresses.  On the other, ping &
ssh both saw the scope id and handled it without complaint.


> Workarounds:
> 
> * don't use mDNS (.local names) to find NFS servers; or
> * configure mdns4[_minimal] instead of mdns[_minimal] so .local names
>   resolve to IPv4 addresses

Yea there are workarounds, but I think this use-case is a sensible one
that should be supported.

My home has provider-assigned addressing via DHCPv6 PD, so it isn't
static.  ipv6 wisdom might suggest ULA + DNS instead.  That requires
static addressing or dynamic DNS - both of which are overkill for home
users.  mDNSv6 has been providing a good solution to exactly this.

Ross