Subject: [SAVA] Conclusions from SAVI Workshop at IETF 71

From: christian.vogt at nomadiclab.com (Christian Vogt)
Date: Sun, 13 Apr 2008 21:20:40 +0300

Dear folks,

during our workshop at IETF 71 in Philadelphia, we concluded on three
steps to be taken in order to convince IESG and IAB that establishing
a SAVI working group is a good idea:

(1)  Finalize proposed working group charter

      We agreed on revising the requirements stated in the current
      charter version.  The current charter version is very ambitious.
      Although we should strive to meet the requirements it lists,
      leaving them in the charter would mean that we have to meet them.
      That may in some cases be hard, in others even unfeasible.

(2)  Finalize problem analysis

      We agreed on adding rationale for the establishment of SAVI to
      the problem analysis by Fred and Danny.  The current version
      includes an excellent overview of threats that IP source address
      spoofing can cause.  It also has a great summary of existing IP
      source address validation techniques.  What it is currently
      missing is a statement of where the existing techniques fall
      short, and why we need SAVI.

(3)  Decide on desired trade-off between security and simplicity of
      to-be-developed SAVI solution

      The IP Source Guard that we have so far considered as a potential
      solution approach is very lightweight.  It doesn't break anything
      and can hence be enabled by default.  But it is not bullet-proof.
      In particular, it assumes that a malicious host won't spoof
      address configuration traffic, such as Neighbor Discovery or DHCP
      messages.  I would like to confirm on this list that SAVI should
      take a similar lightweight approach as the IP Source Guard.
      Please send comments.

      Personally, I strongly favor the lightweight approach.  More
      heavyweight approaches quickly lead to complexity, which doesn't
      contribute to convincing operators that they should switch the
      SAVI feature on.

I will follow up with a revision of the charter proposal, and suggest
rationale text for the problem analysis.

Kind regards,
- Christian