[ntp:questions] Re: NTP Server abuse

Brad Knowles brad at stop.mail-abuse.org
Thu Dec 2 01:37:37 UTC 2004

At 8:32 AM -0500 2004-12-01, mayer at gis.net wrote:

>  That would shut out just about eveeryone since the standard startup
>  interval is 64 seconds, but lets assume we make that suitable
>  adjustment.

	The point is that we can easily characterize the behaviour of 
proper clients, determine fudge factor, and then say that anyone 
beyond the fudge factor is an abuser.  The algorithms for proper 
behaviour are well known, and the samples would be taken over a long 
enough period of time to account for higher traffic during startup.

>  Nothing. We still have plenty of NTP V3 clients/servers out there.
>  With pool moved to SRV, they don't get the benefit of the pool.

	You'll have to talk to Adrian, but I don't think that 
pool.ntp.org is likely to move to SRV until you've got much better 
than 50% penetration of SRV-aware ntpd implementations out there.

>  NTP V4 supports KOD. The people running the pool can demand that anyone
>  who wants to use it obeys the rules or they won't get service.

	They do that already.  They still get buried.

	The issue is what can/should you do to try to protect yourself 
against existing code already out there, and any new dain-bramaged 
implementations that may come along.

>  Couple of years if we don't get more programming talent to help
>  define the architecture, lay out the implementation, and get things
>  working.

	In the meanwhile, we have operational problems that we need to address.

>  The pool servers should be running the latest code as far as is
>  possible and they should drop abusive (too frequent) clients.

	Already being done.  We need to do more.  Some servers have 
already dropped out because they were getting excessive packet rates 
of queries from clients that were ignoring the KOD response, etc....

	We need to figure out what else we can do with the existing code 
and the existing clients.

Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.

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