[Dshield] Possible solution for ISP (was DShield's public goals)

Valdis.Kletnieks@vt.edu Valdis.Kletnieks at vt.edu
Sat Jan 14 07:39:58 GMT 2006

On Fri, 13 Jan 2006 10:08:31 CST, Laura Vance said:

> The ISPs don't have to start blocking until a majority of ISPs are 
> onboard with the system.

Exactly the point.  Not only do they not have to start blocking, they literally
*can't* start blocking. As a result, you have a very *large* dis-incentive to

Profit margins in the ISP arena are razor thin - it's quite possible for an ISP
to lose money on a customer that generates *one* help desk call per year.  As a

1) Yours is not the only scheme looking for deployment - and they can't afford
to deploy all of them.  There simply isn't enough money to go around.  So,
given 5 proposals, and only enough resources for 2 - which 2 do you support?
Keep in mind that the 3 you don't support may end up stillborn - and the 2 you
decided to support may *also* not work if your competitor decides to support 2
others instead.  All the ISPs have to *agree* on which 2 of 5 to support -
*before* you have any actual deployment experience with any of the 5.

2) A good trick to pull on your competitors is to announce you'll also support
their pet proposal, and after they deploy, announce you're not going to,
causing them to expend resources.  You're betting your business plan on your
competitor's announcements that aren't under your control - never conducive to
peaceful sleep.

3) It may come as a shock, but there are rogue ISPs out there, which will *say*
they're participating, but in fact don't bother to. You remember Comcast's big
"We will block port 25" PR-fest a while ago?  How's that working out?  Well, we
can check SenderBase:


"showing 1-50 of 49705".  Yow. Lots of magnitude 5 and 6 entries. For
comparison, listserv.vt.edu has been generating a relatively minor 30K emails
per day off-campus per day of late, and only gets a magnitude 4.4.  So *each*
of those top 50 is pushing a quarter million e-mails per day and more.
(Question - why are only 17 of the top 50 their official outbound mail servers,
and why are they not the top 17? ;)

4) You fail to address what to do about address space that lies outside the US,
or that is allocated to entities outside the US but has BGP announcements
sourced inside the US.  Do you block them, or allow them? Discuss the
challenges of dealing with (3) when the offender is on another continent.

5) There's also a very real possibility that unless your scheme has some sort
of legislative backing, that a participating ISP could get sued into bankruptcy
by a non-participating competitor ISP for restraint-of-trade issues.

> The basic idea is very flexible, but it seems that all you are trying to 
> do is dismiss it or shoot it down with statements that have already been 
> addressed.  If you spent the same effort helping to cultivate the idea 
> it would become a better system that could have ISPs jumping onboard.

Simply repeating "ISPs dont' have to do this till they've all deployed it"
because it's your mantra doesn't mean you're actually addressing the real
problem, which is that you're asking some 3,000 ISPs to agree to deploy
something that's untested, cannot be tested until their competitors also deploy
it, and which they get no benefit from until it's fully deployed, and you're
not making an actual *business case* for the ISP to shell out all these
up-front resources, when the ISP would much rather put resources into projects
that have either immediate or incremental gain, so they see benefits right off
the bat.

As Fergie pointed out, getting enough ISPs to deploy this will be difficult,
given that even no-brainers like BCP38 (which *does* have immediate and
incremental benefits for the ISP when they deploy, whether or not their
competitors do as well) are only deployed by some 75% of the address space.

In fact, the fact that the MIT Spoofer project is having trouble even getting
an accurate *estimate* of how many places deploy BCP38 should be a big warning
sign. See http://momo.lcs.mit.edu/spoofer/ for details....

And as Fergie will attest, if you're thinking that *I* am being negative on
your idea, you're in for a very rude awakening if/when you try to sell your
idea on the IETF and NANOG lists (if you don't understand why you'll be on
those lists to sell your idea, you're in over your head).  

Vernon Schryver got so tired of hearing modifications on the same exact anti-spam
ideas by people who didn't realize that maybe the idea had been already thought
of, examined, and discarded as unworkable multiple times, that he wrote this:


(For bonus points - why did Vernon put the "critical thinker" entry on there?)
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