Re: [secdir] secdir review of draft-sakane-dhc-dhcpv6-kdc-option

Masahiro =Rhythm Drive= Ishiyama <masahiro@isl.rdc.toshiba.co.jp> Mon, 02 July 2012 04:59 UTC

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Date: Mon, 02 Jul 2012 13:59:16 +0900
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From: Masahiro =Rhythm Drive= Ishiyama <masahiro@isl.rdc.toshiba.co.jp>
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Subject: Re: [secdir] secdir review of draft-sakane-dhc-dhcpv6-kdc-option
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	At first I thought that it might be good to leave section 4.1,
	but now I changed my mind. I think the order of the preference
	might depend on the running environment: some people prefer
	"secured" one, some people prefer DNS...  So I'd like to make
	the order configurable and move section 4.1 to appendix, as a
	hint for implementation.

masahiro

>>>>> On Wed, 27 Jun 2012 15:00:29 -0400, Sam Hartman <hartmans-ietf@mit.edu> said:
 > 
>>>>> "t" == t p <daedulus@btconnect.com> writes:
t> Just to make public what I have hinted at privately, I think that steps
t> in section 4.1 may be somewhat underspecified.
 > 
t> A related issue is that section 4.1 prefers DNS to DHCP for Kerberos
t> information but the Security Considerations stress the weakness of
t> DHCP and recommend authenticating DHCP.  What if DHCP is secure
t> and DNS is not?  Should DNS still be preferred?
 > 
 > Yes probably.
 > DNS has been and will continue to be the dominant way to discover KDCs.
 > I see this as a specialized DHCP option for certain deployments, not
 > something you'll see in the enterprise for desktops or laptops as an
 > example.
 > I mean some people may deploy it, but I suspect that you won't see it in
 > most situations where DNS works well today.
 > So, basically in all cases, including preconfigured DNS servers, I'd
 > expect DNS to be preferred.
 > 
 > Note that choosing the right KDC does impact availability--if you have
 > the wrong KDC it won't work.
 > In general though, choosing the wrong KDC does not compromise
 > authentication. It's a bit more complex than that, but KDC location has
 > not generally been considered  security sensitive.
 >