UUNet Offer New Protection Against DDoS

Thu Mar 4 17:19:21 UTC 2004

This sounds like a good idea for us to consider. I think DoS attacks
typically get erased in the 95% discard a lot of people use in billing
though, but it still has value for the customer.

Thanks!

Jason

-----Original Message-----
From: owner-nanog at merit.edu [mailto:owner-nanog at merit.edu] On Behalf Of
Mark Kasten
Sent: Wednesday, March 03, 2004 5:35 PM
To: nanog at merit.edu
Subject: Re: UUNet Offer New Protection Against DDoS

We actually accept up to the customers aggregate.  So if they have a
/16, they can tag the whole /16.  And we do not tag no-export.  I saw
some time ago on a list, and I think Bill Manning suggested it, that if
you are getting bits for unused address space, to announce that address
space (up to host specific) with the DDoS community string.  That keeps
the packets off of your link and thus you don't get charged for them.
The same can be done in reverse.  We have a customer that is advertising
their larger block with the DDoS community string, and then advertising
the addresses they are actually using more specifically, so we blackhole
everything less specific.  These are a couple of applications that can
be utilized if you don't tag no-export and accept more than just /32's
within their address space.  FWIW.

Also, we are utilizing Juniper's DCU for tracebacks, which makes life
MUCH easier when tracing an attack.  :-)  SNMP polling the DCU counters
every few minutes is relatively fast and painless, and provides quick
results.

Mark

Lumenello, Jason wrote:

Oh, and I strip their communities, and apply no-export, on the first
term of my route map so the /32 does not get out. Of course my peer
facing policy requires specific communities to get out as well (belt and
suspenders).

This method works very well, and you do not have to give up length
restrictions or maintain two sets of customer prefix/access lists.

Jason

	-----Original Message-----
	From: Lumenello, Jason
	Sent: Wednesday, March 03, 2004 4:52 PM
	To: 'Stephen J. Wilcox'; james
	Cc: nanog at merit.edu
	Subject: RE: UUNet Offer New Protection Against DDoS

	I struggled with this, and came up with the following.

	We basically use a standard route-map for all customers where
the

first

	term looks for the community. The customer also has a
prefix-list on

their

	neighbor statement allowing their blocks le /32. The following
terms

(term

	2 and above) in the route-map which do NOT look for the customer

discard

	community, have a different standard/generic prefix-list
evaluation

which

	blocks cruft and permits 0.0.0.0/0 ge 8 le 24.

	By doing this, I only accept a customer /32 from his dedicated

prefix-list

	when it has the DOS discard community, otherwise I catch them
with the

ge

	8 le 24 in the following terms.

	Jason Lumenello
	IP Engineering
	XO Communications

		-----Original Message-----
		From: owner-nanog at merit.edu
[mailto:owner-nanog at merit.edu] On Behalf

Of

		Stephen J. Wilcox
		Sent: Wednesday, March 03, 2004 3:48 PM
		To: james
		Cc: nanog at merit.edu
		Subject: Re: UUNet Offer New Protection Against DDoS

		I'm puzzled by one aspect on the implementation.. how to
build your
		customer
		prefix filters.. that is, we have prefix-lists for
prefix and

length.

		Therefore
		at present we can only accept a tagged route for a whole
block.. not

	good

		if the
		announcement is a /16 etc !

		Now, I could do as per the website at secsup.org which
means we have

a

		route-map
		entry to match the community before the filtering .. but
that would

	allow

		the
		customer to null route any ip.

		What we need is one to allow them to announce any route
including

more

		specifics of the prefix list - how are folks doing this?

		Steve

		On Wed, 3 Mar 2004, james wrote:

			Global Crossing has this, already in production.
			I was on the phone with Qwest yesterday & this
was one
			of this things I asked about. Qwest indicated
they are
			going to deploy this shortly. (i.e., send routes
tagged with
			a community which they will set to null)

			James Edwards
			Routing and Security
			jamesh at cybermesa.com
			At the Santa Fe Office: Internet at Cyber Mesa
			Store hours: 9-6 Monday through Friday
			505-988-9200 SIP:1(747)669-1965

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