Re: Confirmation to advance: draft-ietf-6man-ipv6only-flag-05

[Nick Hilliard <[e-mail]>]

David Farmer wrote on 24/05/2019 14:35:
> On Fri, May 24, 2019 at 3:59 AM Nick Hilliard <[e-mail]> wrote:
>     the usual ietf position is that operational misconfig - including
>     daemons crashing - is out of scope for protocol development.  If it's
>     out of scope, there's no real issue regarding consensus.
> 
>     Obviously, from an operational point of view, if DHCP service is
>     important on a network, the operator is at liberty to install redundant
>     servers / relays.
> 
> WHAT ARE ARE YOU SAYING?

nothing more than the sober reality of GIGO - garbage in, garbage out. 
DHCP, as a protocol, expects correct configuration.

Is it a problem with the protocol if someone mis-types a MAC address in 
the config?  Or specifies the wrong next-hop gateway?  Or makes a 
mistake in an autoconfig URL?  All these things could be fatal for the 
device under configuration.  Fixing this is not a protocol-layer problem.

> The IETF SHOULD NOT concern itself with 
> accidental misconfiguration? And SHOULD only create fragile and brittle 
> protocols? The IETF SHOULD NOT seek robustness in its protocols?

These issues are, to some degree at least, orthogonal to each other: you 
can build solid protocols which are inherently susceptible to problems 
with misconfigs. On the other hand, implementations can be built to work 
around this by implementing sanity checking.

Regarding misconfigs and crashing in general, DHCP has been around for a 
long time. This means that people understand how it works - i.e. 
misconfigs can usually be solved quickly - and the implementations are 
generally pretty robust - i.e. crashes are rare and if you need 
resilience, you can use multiple separate servers / relays (a 
protocol-layer feature).

Nick