-----Original Message-----
From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Mark Kasten
Sent: Wednesday, March 03, 2004 5:35 PM
To: nanog@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@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@merit.edu [mailto:owner-nanog@merit.edu] On Behalf

Of

Stephen J. Wilcox

Sent: Wednesday, March 03, 2004 3:48 PM

To: james

Cc: nanog@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@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