Re: Blackholes and IXs and Completing the Attack.

From: Rick Astley (no email)
Date: Sat Feb 02 2008 - 20:02:06 EST

  • Next message: Roland Dobbins: "Re: Blackholes and IXs and Completing the Attack."

    While I am not sure I fully understand your suggestion, I don't think it
    would be that hard to set up manually.

    Sure it would require asking the individual peers for their black hole
    communities, but of they don't have one they are unlikely to honor the
    infrastructure you describe anyway.

    Assume your network is set up to discard packets marked with community
    13005:666

    Get a list of your peers blackhole communities, when you announce the route
    from a location on your network, tag it with community 13005:666 but also
    1111:777, 2222:888 etc. for the individual peers from the source. This
    prevents you from having to update multiple policies in multiple locations
    for each attack.

    As long as they accept the /32 announced to them with their black hole
    community, they should discard the traffic without sending it to you.

    Not all peers will have a blackhole community, but you need some way to know
    when the attack is over to know when to withdraw the route, and they are
    useful for this.

    If you are real lazy, on the router you announce the black hole from, add an
    export policy that says from community 13005:666, then community add
    1111:777, 2222:888 etc.

    This way you only need to:

    1. Update one policy in one place when peers change
    2. Announce the route from one location adding one community to it.


  • Next message: Roland Dobbins: "Re: Blackholes and IXs and Completing the Attack."





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