There are still a few problems with this draft. The first is that it uses a
nonstandard and somewhat odd encoding to deliver the URI and Lifetime values.
These should simply be delivered as separate options, leaving out the whole
Luritype complication. The argument might be raised that the Luritype field
provides some sort of future-proofing, but this future-proofing can as easily
be attained with another DHCP option code, so it's unnecessary.
Secondly, this text ought to be expanded:
The choice of the Valid-For value is a policy decision for the
operator of the DHCP server. Like location URIs themselves, it can
be statically configured on the DHCP server or provisioned
dynamically (via an out-of-band exchange with a Location Information
Server) as requests for location URIs are received.
To:
The choice of the Valid-For value is a policy decision for the
operator of the DHCP server. Like location URIs themselves, it can
be statically configured on the DHCP server or provisioned
dynamically (via an out-of-band exchange with a Location Information
Server) as requests for location URIs are received. DHCP server
operators are advised not to configure a valid-for lifetime that is
greater than half the minimum configured lifetime for DHCP leases,
since this could result in stale configuration information on the
DHCP client and potential loss of service.
Thirdly, this text is simply wrong, and indeed specifically contradicted by
RFC3396:
Per [RFC2131], subsequent LocationURI Options, which are
non-concatenated, overwrite the previous value.
I don't think this is a huge problem, but I think the text should say this:
It is not meaningful to configure multiple LocationURI options. DHCPv4
servers and clients conforming to RFC3396 will not permit this; DHCPv6
servers and clients can be configured this way, but the behavior when so
configured is undefined. Therefore, DHCPv6 server operators are cautioned
not to configure more than one such option.
Section 3.2 suggests that options shouldn't contain certain potentially harmful
values, but this is a toothless restriction, since an attacker can simply
ignore it. In order for it to be effective, Section 3.2 should insist that
DHCP clients reject forbidden URI formats. Of course, this too is somewhat
toothless, since any list of forbidden URI formats will necessarily fail to
mention any future potentially harmful URIs that could arise. It would be
better to list which URIs _are_ permitted, and require the client to reject any
URI that is not permitted. The document is already set up to do this, but
doesn't _actually_ do it, so fixing this should be quite easy.
Sorry for not catching all of this sooner—the previous review of the document
was rudely interrupted by the Paris IETF meeting... :)
Aside from these objections, which I think are easy to address, I have no
problem with the document proceeding.