Subject: [mif] DNS server selection issues 1: Security and conflicts

From: <[email-masked]>
Date: Thu, 11 Nov 2010 03:22:21 +0100

Hi,

I'm considering replacing current security considerations with following text. Essentially not including policy conflict resolution in this document, but stating it is resolved elsewhere. After all, the conflict resolution is a common problem across any configuration element (DNS selection, more specific route, NTP, whatever). We should have uniform solution.

--
   The host SHOULD implement DNSSEC to have capability to validate DNS
   responses from any of its interfaces.

   A node with multiple interfaces may receive conflicting DNS server
   selection rules from its interfaces.  These conflicts may be caused
   by unintentional misconfiguration or by an attack done on purpose.
   Even a single specific DNS server selection rule from one interface
   can be considered is a conflict against default DNS server
   configuration from another interface.

   The conflicting policy problem is a generic problem present with any
   kind of configuration element a node may receive from its interfaces.
   A node must have a solution in place for conflict resolution and for
   preventing attackers injecting malicious DNS server selection
   policies.  As the solution must be generic and uniform across
   different configuration elements, it is not covered in this document.
   (Editor's note: it may for example be such that DNS server selection
   information is only accepted via trusted interfaces.  Trusted
   interface is an implementation/deployment specific choice).
--

Any comments?

Best regards,

Teemu