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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: smurf, the MCI-developed tracing tools (was Re: Bogus announcement)
Karl Denninger writes... > Then you damn well better not be permitting any of the following: > > 1) Forged source addresses (this CAN be stopped with specific filters > on your interfaces, although some will bitch about the performance > impact - depending on their specific choices) Yet another case for pressing (now) ARIN (and others who allocate address space) to do address allocation in reasonable chunk sizes instead of forcing providers to accept little bits of address space a piece at a time. Prefix volume on BGP would be helped, too, by having fewer little pieces scattered all around. And with address space now on a paid basis, in theory people will generally ask for what they expect to need (there will be exceptions but they should be easy to spot), so there is more reason to actually give out requested allocations that are not obviously inflated. > 2) Directed broadcasts (which are used to "create" these DOS attacks by > bouncing the attack off a particularly-well-connected location, > USUALLY a provider's internal infrastructure). > > Block both of those and Smurfs would disappear. If you can trace the TRUE > source of such an attack quickly, people will go to jail for this. The only > reason they are popular is because the source addresses CAN be forged. Specific information is always helpful. Unfortunately, if it has been given on NANOG, it can be missed due to the high noise level (yet another issue we need to work on). Would config examples in IOS and gated be too much to ask for (if someone only knows one, someone who knows the other should follow up). > THIS CAN BE PREVENTED. Agreed. Let's make it easy. -- Phil Howard | [email protected] [email protected] [email protected] phil | [email protected] [email protected] [email protected] at | [email protected] [email protected] [email protected] milepost | [email protected] [email protected] [email protected] dot | [email protected] [email protected] [email protected] com | [email protected] [email protected] [email protected]
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