Default route (IPv4) demolished by destroying clone (gif/gre) interface

Yar Tikhiy yar at comp.chem.msu.su
Thu Aug 17 06:50:23 UTC 2006


On Wed, Aug 16, 2006 at 12:15:25PM -0500, Brooks Davis wrote:
> On Wed, Aug 16, 2006 at 07:58:44PM +0400, Yar Tikhiy wrote:
> > On Wed, Aug 16, 2006 at 09:54:19AM -0500, Brooks Davis wrote:
> > > On Wed, Aug 16, 2006 at 10:23:13AM +0200, Stefan Bethke wrote:
> > > > 
> > > > Ouch. Don't ppp(8), OpenVPN etc. destroy the tun interface they're  
> > > > using when they exit?  Flushing all routes then would be rather  
> > > > harmful.  I'm glad I haven't updated to a newer -stable yet then :-)
> > > 
> > > In general, no since tun interfaces can not be destroyed.
> > 
> > Did you mean "in particular"? :-)
> > 
> > The problem can be triggered by destroying any interface that can
> > be destroyed.  Just imagine getting rid of a defunct gif tunnel on
> > a remote router, or removing an unused vlan, and totally losing
> > connectivity to the router due to its default route having been
> > flushed.  The scenario still can be quite unpleasant.  I'd rather
> > change the default for $removable_route_flush to NO and let the
> > kernel choose which routes should be flushed upon the physical
> > ejection or software destruction of an interface.  Note that this
> > doesn't include static_routes_${ifn}, which are handled separately
> > by pccard_ether_stop().
> 
> Agreed.  That code shouldn't be on by default.  I've disabled in it HEAD
> and will MFC in a few days.  As another poster said, I'm not even sure
> it should exist as an option.

Much appreciated!

-- 
Yar


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