[nsp] ipv6 address ::X/128 on Cisco router

[Gert Doering]

Hi,

On Fri, Jun 18, 2004 at 09:48:49PM +0100, Stephen J. Wilcox wrote:
> i thought (and cant find a link to confirm this so i may be wrong..) that 127/8 
> is implicitly dropped on ingress as it is not a valid address for a router?

The hosts requirements RFC requires that packets with such a source or
destination address never appears on the wire.

Recent worms have demonstrated that Microsoft programmers don't know this
- Windows worms have been seen sending out packets with a source IP of
127.0.0.1 (source port 80) to random destinations, and both C and J
routers happily forward them, unless uRPF (or similar) is applied.

gert

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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de