Subject: Re: illegal network routes and a ponderance
To: None <tech-net@netbsd.org>
From: David Young <dyoung@pobox.com>
List: tech-net
Date: 02/19/2003 22:51:44
On Wed, Feb 19, 2003 at 07:11:56PM -0500, der Mouse wrote:
> >> Yes, I ran into this myself, and hacked on the ARP code to make ARP
> >> entries interface-specific. The result has some problems [...]
> > I think if you satisfy the following:
> > . Default is to publish on all interfaces.
> > . If an interface is specified, publish only on that interface
> > ... then I say clean it up and submit it.
>
> It doesn't. It makes ARP entries interface-specific. If you want to
> publish on all interfaces, you have to add N ARP entries, and you can't
> actually do that because ARP entries are actually host routes with the
> LLINFO flag set, and you can't have multiple distinct routes with the
> same destination.
*snip snip*
> The Jargon File entry for "uninteresting" says, in part,
>
> Real hackers (see
> toolsmith) generalize uninteresting problems enough to make them
> interesting and solve them -- thus solving the original problem as a
> special case
Speaking of *interesting* problems, it is an interesting problem
that in NetBSD you CANNOT have multiple distinct routes with the same
destination. This has unexpected effects in wireless networks, where
sometimes it is desirable to keep a remote route to a host for the
purposes of IP traffic, but also to keep a link-local route to the
same host for the purpose of route set-up and discovery.
Excuse me for plugging my pet bug in NetBSD. =)
Dave
--
David Young OJC Technologies
dyoung@ojctech.com Engineering from the Right Brain
Urbana, IL * (217) 278-3933