nanog mailing list archives

Re: If you have nothing to hide


From: <bdragon () gweep net>
Date: Mon, 5 Aug 2002 12:07:46 -0400 (EDT)


Thus spake <bdragon () gweep net>
<snip>
our packets. While I'm certainly in favor of anything edge providers can
do to eliminate denial of service attacks based on source-routing,
I certainly don't want anything further.
<snip>

denial of service based upon source routing? I hadn't heard of any denial
of service attacks of that sort.

Disabling source-routing is like filtering icmp, sure you might block
a few abuses, but more often than not, you are throwing out legitimate
traffic.

I can't come up with any legitimate reason to use source-routed packets today.
If your routers even support them, they probably consume orders of magnitude
more processing power than normal packets; that is enough reason to disable
source-routing, not to mention the security implications.

S

Validation of routing policy to ensure others aren't abusing you (pointing
default, for example). As for orders of magnitude, once an IP option is
in a packet, the damage is essentially done, otherwise looking up the
path to an address in the options is no more impactive than looking up the
address in the original destination field. source-routing only has security
implications to those with defenses which permit traffic through some type
of backdoor. The backdoor has more security implications than the
source-routing, since it may be compromised in other manners.


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