nanog mailing list archives

Re: [c-nsp] DNS amplification


From: Jared Mauch <jared () puck nether net>
Date: Mon, 18 Mar 2013 09:25:53 -0400


On Mar 17, 2013, at 8:55 PM, Christopher Morrow <morrowc.lists () gmail com> wrote:

On Sun, Mar 17, 2013 at 6:36 PM, Arturo Servin <arturo.servin () gmail com> wrote:

       They should publish the spoofable AS. Not for public shame but at least
to show the netadmins that they are doing something wrong, or if they
are trying to do the good think is not working.

       Or at least a tool to check for your ASN or netblock.

I don't disagree, but I'd point out that there are likely easier
places to do bcp38 than others in everyone's network(s)... So, 'I do
bcp38' unqualified is not as helpful, especially when almost all
consumer grade links are bcp38 by default, which is likely where a
bunch of this measurement originates. (well, I suspect a bunch of it
is from consumer-grade links anyway)

(Not sure how this made it from c-nsp to nanog, but ...)

uRPF/BCP38 is an important part of a global solution.  Similar to open-relays, smurf amplifiers, and other "badness" on 
the network, one must assist the global network by deploying it where it makes sense.

Deploying it at your customer ports may make sense depending on your network.  Deploying it on peers may also make 
sense.

I think having a simple set of locations where people actually deploy it is critical, eg:

Colocation Network
Server Lans
VPS Lans
Static Routed Customer Edge

This should be the default, and something I've pushed at my employer for years.  

If you do nothing, you can expect nothing as the result.  If you attempt do so something, you can at least get an idea 
of where it's not coming from.  At least target these easy edges of the network where there is some value.

- Jared

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