Why do packets to 127.255.255.255 cause dial-up?

[Paul Civati]

Nik Clayton <nik at freebsd.org> wrote:

> This is a bit of a noddy question, but I'm damned if I'm exposing my
> ignorance to the entirety of the world via -questions.  The whole of 
> the UK (and certain small European countries, hi Brad) should be more
> than sufficient.

:)

> I'm going to track down the whys and wheres of Samba doing this in a minute,
> and block it.  That should be fairly easy with some dial filters.

I saw this the other day, and it was caused by an /etc/hosts that
looked something like this:

127.0.0.1    localhost your.host.name

So, it seems to pick up the IP network it's on from the IP of the
hostname.

Which may be your problem, may be not.

> What I don't understand is how packets for the 127/8 broadcast address are
> getting on to tun0 in the first place.  Why aren't they staying on lo0 like 
> they should be?

That is odd.

> There's obviously a gap in my understanding of how IP works.

FWIW, I would agree with you.

-Paul-