At 14:36 01/06/01 -0400, Mark Mentovai wrote:
Walter Prue wrote:
I came up with a solution for networks with ISP connections to deal quickly with DDOS attacks without having to be able to work with a network technician at the ISP for immediate relief. If the ISP agrees, install a second low speed connection to the same router your primary router BGP peers with. Through this low speed connection you run a second bgp session advertising the /32 that is being attacked by the DDOS. You mark the /32 as NO-ADVERTISE so the route doesn't leave the border router.
Or, without adding an extra connection, negotiate a NULLROUTE community with your upstream provider. This would be a wonderful addition to the well-known BGP communities. I'll bring this up on IDR.
Assuming not adding the extra connection, this means that upstream prefix filtering, so that one can't mistakenly inject 255 /24s rather than a single /16, would go out the window. Now think about /32s and what the routing tables will start to look like. Now consider that the upstream would also want to send to its upstream Tier-1 the NULLROUTE /32 as well so that his bandwidth is not eaten up as well and we have a situation whereby routing table size will triple in size every year. -Hank
Mark