Solution: Re: Huge smurf attack

Brandon Ross bross at
Wed Jan 13 07:20:29 UTC 1999

On Tue, 12 Jan 1999, Dean Anderson wrote:

> Actually, I think all major providers use automatic provisioning systems
> which generate router configs. They don't need to rely on router vendors to
> set particular defaults.  If all major providers made sure their
> provisioning systems turned off directed broadcast, a lot of the problem
> would go away.
> So "Router defaults" is a lame excuse for ISP's.  Even little ISP's have a
> list of things they have to setup, (eg ip classless, subnet zero, etc)
> which have "legacy" or otherwise inappropriate defaults.

We don't ask our vendors to provide equipment with directed broadcast
turned off by default for our own use or use by any clueful operator.  The
reason we require directed broadcast to be turned off by default is so
that when a less-than-clueful operator gets a hold of the same box, they
don't become yet another smurf amplifier that ends up being used to attack
us. If and when I have the leverage with a vendor to get this implemented,
I use it, every single time.

Brandon Ross            Network Engineering     404-815-0770 800-719-4664
Director, Network Engineering, MindSpring Ent., Inc.  info at
                                                            ICQ:  2269442

Stop Smurf attacks!  Configure your router interfaces to block directed
broadcasts. See for details.

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