Subject: [Dhcpv6bis] Handling of loopback interfaces (Ticket #48)?

From: <[email-masked]>
Date: Mon, 11 Aug 2014 07:49:46 +0000

Ticket #48 " Clarify that configuration received over interface X applies to interface X only"
seems to reference section:

16.1. Address Assignment
   When a client sends a DHCP message to the
   All_DHCP_Relay_Agents_and_Servers address, it SHOULD send the message
   through the interface for which configuration information is being
   requested.  However, the client MAY send the message through another
   interface attached to the same link, if and only if the client is
   certain the two interfaces are attached to the same link.  The client
   MUST use a link-local address assigned to the interface for which it
   is requesting configuration information as the source address in the
   header of the IPv6 datagram.

   When a client sends a DHCP message directly to a server using unicast
   (after receiving the Server Unicast option from that server), the
   source address in the header of the IPv6 datagram MUST be an address
   assigned to the interface for which the client is interested in
   obtaining configuration and which is suitable for use by the server
   in responding to the client.

I see a problem to do the clarification simply as the subject of the ticket states.
That would disable use of DHCPv6 to assign IPv6 address to loopback interfaces that
are without direct link attachment.

I think we should allow:
... MAY send the message through another interface if and only if the interface
is logical (i.e. loopback) interface without direct link attachment or the client is certain
the two interfaces are attached to the same link.

Another possibility would the create a new option to request address for non-attached interface,
but that would be more complicated, wouldn't it?
--
Jyrki