Re: Clueless service restrictions (was RE: Anti-spam System Idea)

[John Kristoff <jtk () northwestern edu>]

On Tue, 17 Feb 2004 21:48:18 +0000
Alex Bligh <alex () alex org uk> wrote:

> a) Some forms of filtering, which do occasionally prevent the customer
>    from using their target application, are in general good, as the
>    operational (see, on topic) impact of *not* applying tends to be
>    worse than the disruption of applying them. Examples: source IP
>    filtering on ingress, BGP route filtering. Both of these are known
>    to break harmless applications. I would suggest both are good things.

There are some potential applications that these can break also.  For
example, a distributed application that sends out probes might wish to
use the source IP address of a remote collector that is used to measure
time delay or network path information.  If Lumeta could have tunnels
to a bunch of hosts, send traceroutes to various Internet places through
those tunnels and have the tunneled hosts use Lumeta's IP as the source
IP, they could build a pretty cool distributed peacock map.

It is of course difficult to find a way to use these legitimate types of
apps today without the infrastructure succumbing to attacks such as the
source spoofed DoS traffic floods.

John