North American Network Operators Group

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DDoS mitigation with BGP communities

  • From: Matthew Crocker
  • Date: Mon Jun 14 23:31:01 2004



Hello,

I just experienced my first official DDoS attack against my network. I never realized how helpless I was :(. I had roughly 70 mbps of traffic aimed at one IP. The IP wasn't even in use, I'm assuming someone typed the wrong IP and meant to send it somewhere else. I shut it down by removing the /24 announcement. This was fine except for the customers on that /24. I know my upstreams have special communities I can set via BGP announcements that effectively say 'route packets to this network to null0'. My question is, what do I need to put on my router (i.e. code examples) to inject the /32 into the BGP announcements. I try to be a good net citizen and announce aggregate blocks. I had to break my /21 up so I could announce everything but the /24 in the middle. Any help would be greatly appreciated.

Routers are a couple 7500 series running 12.0.xx


-Matt