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Re: DOS attack against DNS?
From: Mark Andrews <Mark_Andrews () isc org>
Date: Tue, 17 Jan 2006 10:27:59 +1100 (EST)


In article <Pine.LNX.4.64.0601160943150.30093 () twin uoregon edu> you write:

On Mon, 16 Jan 2006, Paul Vixie wrote:


Mark_Andrews () isc org (Mark Andrews) writes:

    For repeat offenders create a list of networks that won't
    implement BCP 38 and collectively de-peer with them telling
    them why you are de-peering and what is required to
    re-establish connectivity.  It is in everyones interests
    to do the right thing here.

people inside one of the largest networks have told me that they have
customers who require the ability to bypass BCP38 restrictions, and that
they will therefore never be fully BCP38 compliant.  i've asked for BCP38
to become the default on all their other present and future customers but
then there was whining about bankruptcy, old outdated equipment, and so on.
sadly, there's no way to de-peer this network, or any other multinational,
and so there will be no "peer pressure" on them to implement BCP38.

Consider people in the rest of the world who may purchase simplex 
satellite links. By definition they inject traffic in places they aren't 
announcing their route from.

        But they don't need to be able to source all of 0/0.  They
        need to be able to source particular addresses which they
        have.  If the end point of the satellite link is dynamic
        then they need to souce netblocks.  The satellite company
        should be able to supply a complete list so filters can be
        setup appropriately.

        BCP 38 isn't all or nothing.  You do the best you can.  You
        limit the exposure.

        In this case if you get spoofed traffic from the satellite
        company's addresses you still talk to the satellite company
        to address the problem.  If they have static address
        assignment it should be a easy job to trace the offending
        traffic back.  If they have dynamic assignment then things
        get harder.

        It should be possible to prevent any "owned" box (other
        than a router) spewing out spoofed traffic to the net as a
        whole.  "owned" routers are a different kettle of fish.

        This is not a new problem.  Sooner or later goverments will
        mandate this sort of filtering if the networking community
        as a whole don't do it and they may not leave room to support
        satellite down links.  Think manditory strict unicast reverse
        path filtering everywhere.

so, it's either not in everyone's interests to do the right thing, or there
is still a huge variance in what's considered "the right thing".  either
way, we're (the internet is) SCREWED until we (that's "we all") fix this.

(if you're not seeing spoofed-source attacks, bully for you!  i didn't see
one today, either, but leaving this tool in the bad-guy toolbox makes us all
unsafe, no matter how much or how little they may be using it this day/year.)


-- 
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Joel Jaeggli          Unix Consulting         joelja () darkwing uoregon edu
GPG Key Fingerprint:     5C6E 0104 BAF0 40B0 5BD3 C38B F000 35AB B67F 56B2




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