Re: Enabling SLAAC for IPv6 by default

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Tue, 25 Sep 2018 22:41:08 +0200
    From:        Joerg Sonnenberger <joerg%bec.de@localhost>
    Message-ID:  <20180925204108.GA5450%britannica.bec.de@localhost>

  | I'm personable more in favor of removing the in-kernel RA support. I do
  | not think that automatic temporary address generation should be done by
  | default for an OS that is often used as a server. Consider a mail server
  | were you suddenly start running into graylisting every day...

This suggests more that there should be an address selection API, and
applications should use it - not to the stage of selecting a particular
address (which usually requires too much knowledge to perform properly)
but to be able to specify what style of address is needed for a particular
application.

MTAs (and servers in general - the MTA is a bit special as, as you say, it
also matter sto outgoing connections) would request stable addresses (for
service addresses, perhaps even EIU-64 addresses, or manually configured
ones, so they remain stable over a very long period) - others coudl use 
whatever the system manager picks as the form of stable addressing to use.
Web browsers should probably request temporary addresses.    Other apps
(ssh clients, ...) can do whatever they think best.

But untilo we have an API that allows simple selection of such things (with
fallback to otherw when the desiored form does not exist ... better to 
communicate and be able to send e-mail, even if it does mean waiting out
greylisting, than not to communicate at all if there is no stable addr) then
we will constantly be facing this problem, there simply is no one solution that
is best for all cases.

kre