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Re: Bug#3143: sysvinit init.d/network script buglet



Lukas Nellen wrote:
> >> From: Lukas Nellen <lukas@teorica0.ifisicacu.unam.mx>
> >>
> >> To me, it looks like there is a small bug in the way the networking
> >> gets configured in the base system. The problem is the loopback
> >> network 127.0.0.0. AFAIK, no packet addressed to any address on that
> >> network should ever leave the local host. Instead, the loopback
> >> interface on the local machine has to accept ALL such packets, not
> >> just those sent to 127.0.0.1. Could someone confirm that or point me
> >> to a document which states the contrary?
> 
> MvS> Well I couldn't find it documented, but the way Debian does it now
> MvS> is the same as Solaris 2.5, SunOS 4.1.4 and FreeBSD do it (I just
> MvS> checked).

... and AIX, Digital Unix, Ultrix ...

> What happens if those systems, say, ping 127.0.0.2? Which system
> answers? I'm pretty sure that nothing in 127.x.y.z is supposed to
> leave your system. I remember follwing a discussion somewhere about
> that issue. The problem with packets in 127.x.y.z is the following:

A ping 127.0.0.2 will leave the system, even on the systems mentioned
above.

> I noticed the problem when I saw that rwhod on my debian system sends
> broadcasts on each interface (which makes sense), and that the
> broadcasts on 127.255.255.255 appear on the ethernet (which shouldn't
> happen).

That was a different problem which has been fixed in the latest netstd
package.

> Can you verify the behaviour of the other systems when they connect to
> a random address in 127.x.y.z? After all, the problem isn't what they

100% packet loss on each system (ping).

> BTW, RFC 1009 and 1700 (there might be others) state that 127.x.y.z
> should never appear outside a host. This implies that the current
> configration of the networking system as done in debian is incorrect.

... and all other Unix systems do it the wrong way? I'll go and read
some RFCs now :-).


Thanks,

Peter

-- 
 Peter Tobias                                EMail:
 Fachhochschule Ostfriesland                 tobias@et-inf.fho-emden.de
 Fachbereich Elektrotechnik und Informatik   tobias@debian.org
 Constantiaplatz 4, 26723 Emden, Germany


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