RE: howto disable auto route setup?

Fred Reimer (Fred.Reimer@eclipsys.com)
Tue, 2 Feb 1999 11:25:02 -0500


> -----Original Message-----
> From: owner-linux-kernel@vger.rutgers.edu
> [mailto:owner-linux-kernel@vger.rutgers.edu]On Behalf Of
> Khimenko Victor
> Sent: Tuesday, February 02, 1999 10:15 AM
> To: nconway.list@ukaea.org.uk; mike@roan.co.uk
> Cc: sam@gate.mps.co.uk; linux-kernel@vger.rutgers.edu
> Subject: Re: howto disable auto route setup?
>
>
> In <99Feb2.135347gmt.66309@gateway.ukaea.org.uk> Neil Conway
> (nconway.list@ukaea.org.uk) wrote:
> > Mike Jagdis wrote:
> >>
> >> On Tue, 2 Feb 1999, Sam Mortimer wrote:
> >>
> >> > >Because the ifconfig says that the interface exists on
> that network
> >> > >with that address
> >> >
> >> > ..and subnet mask!
> >>
> >> Huh? Don't get excited - network is defined by address and
> mask :-).
>
> > Vaguely on this topic, I've been wondering if it's
> legal/advisable/safe
> > to have a netmask like 255.255.254.0 ?
>
> > Anyone? The HOWTO is rather ambiguous about it. I think
> it's legal,
> > but am not entirely sure. This also seems to imply a
> broadcast addr. of
> > something like 194.111.1.255 for a network address of 194.111.0.0,
> > presumably that's OK too?
>
> It's Ok from RFC viewpoint but some [old] routers could be
> confused by such
> configurations.

How is this OK from an interface configuration view? Yes, there are
multiple routing protocols that support CIDR, or subnet masks that are less
than the class of network itself. But, AFAIK you can't have a subnet mask
on an >interface< that is less than the class of network. 194 is a Class C
right? So the subnet mask must be at least 255.255.255.0 or 24 bits. What
RFC and what section says otherwise?

Fred

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