North American Network Operators Group
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Re: UUNet Offer New Protection Against DDoS

  • From: Mark Kasten
  • Date: Wed Mar 03 17:50:28 2004

We still implement exact match prefix filtering, but also generate a second "aggregated" prefix-list for customers to match more specifics. If a prefix matches 3561:666 _and_ falls within the DDoS/aggregated prefix-list, we accept it and blackhole it. If a customer announces the more specific without the community, we won't accept it. (No flame wars about exact match filtering please). Yes, that means we maintain two prefix-lists for each customer.
uRPF is another matter. We use policies for prefix-lists on Junipers and prefix-lists on Cisco's, which means that if we want to do strict uRPF for customers we have to generate a third prefix-list/acl? <sigh>

Regards,
Mark Kasten
C&W^H^H^H^Savvis

.

Stephen J. Wilcox wrote:

I'm puzzled by one aspect on the implementation.. how to build your customer prefix filters.. that is, we have prefix-lists for prefix and length. Therefore at present we can only accept a tagged route for a whole block.. not good if the announcement is a /16 etc !

Now, I could do as per the website at secsup.org which means we have a route-map entry to match the community before the filtering .. but that would allow the customer to null route any ip.
What we need is one to allow them to announce any route including more specifics of the prefix list - how are folks doing this?

Steve

On Wed, 3 Mar 2004, james wrote:


Global Crossing has this, already in production. I was on the phone with Qwest yesterday & this was one
of this things I asked about. Qwest indicated they are
going to deploy this shortly. (i.e., send routes tagged with
a community which they will set to null)


James Edwards
Routing and Security
[email protected]
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