Blackholes and IXs and Completing the Attack.

Sun Feb 3 13:17:12 UTC 2008

yes absolutely, if an agreement could be reached - then that is a neater
solution, but I wonder if an agreement could ever be reached in a
timescale that doesn't make deployment of the alternative more
attractive as it doesn't require everyone to agree.

________________________________

From: Rick Astley [mailto:jnanog at gmail.com] 
Sent: 03 February 2008 06:56
To: Ben Butler
Cc: nanog at merit.edu
Subject: Re: Blackholes and IXs and Completing the Attack.

I see your point, but I think maintaining the box for the control
session would also require a decent amount of work.
Presumably, since you must all adhere to some quasi-standard to
communicate with the control peer, you could probably also agree on
creating a standard BGP community (ie. 64666:666 & no-export) to use and
just skip the middle man.

Granted, I am kind of new as well, and I assume if the solution were
that simple more people would be using it.

On Feb 2, 2008 9:07 PM, Ben Butler <ben.butler at c2internet.net> wrote:

	Hi,

	Agreed, but when you have >100 peers that is still a fair bit of
work.  I know technically how to do it and am doing this with transits
but then there are only seven of those.  It is not a question of how or
can, but should / is it valuable / constructive?

	The starting point in the thought process having just done it
for transits was right ok, now how do we sensibly scale this to apply it
at IXes without everyone having to run round contacting everyone else
and to see if there was an easier way of doing things, hence the
suggestion.  Plus it keeps things nice a separated, your IX peering
sessions announce just the main prefixes, the session to the "blackhole
reflector" can be in a separate peer-group and you only send the /32s to
the reflector.  You don't have to worry about who uses which communities
as each member that chooses to peer with the reflector is able to apply
an inbound routemaps of their own choosing to any prefixes they receive
from this reflector at each individual IX.

	Given that an ISP has elected to Complete the attack on a host
that is being DoSed, for whatever reason, and they have chosen to send
blackhole announcements to transit the logical extension seems to be to
automate the sending of them to IXs to try to further cut down on
traffic.  This seems like a easy way, internally you just community tag
on the trigger box for where you want the announcement to go, transit,
internal, customers, IX all,1 2 not 3 - whatever - and BGP sends it out.
Easy, and a single system to send out all updates when you choose to and
easy to remove when you want to take it out again.

	If you subscribe to completing the attack as a strategy, then
the suggestion seemed like an easy way of rolling it out to the next
logical point after transit.

	Kind Regards

	Ben

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