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Re: and now, back to your regularly scheduled discussion topic...
From: guenther () gac edu (Philip Guenther)
Date: Mon, 08 May 1995 22:49:30 -0500


Patrick Horgan said:
and now for something completely different (apologies to M. Python):

ObBug:  i have recently discovered that it is possible to re-export an
imported filesystem under Linux.  to illustrate:

hostA --> exports /usr/share to -access=hostB
hostB --> a linux box.  re-exports /usr/share to everyone
hostC --> not implicitly trusted by hostA, mounts /usr/share

aside from any security concerns, this would certainly thrash your nfsd's.
does anyone have any experience with this?  i have only recently discovered
this, and have not had time to peruse it in depth.


Are you sure about this?  Any system using nfs will allow this, but the
directory they mount from hostB is the mount directory, not the /usr/share
form hostA.

Ah, but Linux uses a user level nfs server, which does a couple odd
things.  Not only will it allow the above, but it exports across
partition boundaries (i.e., if /usr and /usr/local are different
partitions, and you export /usr, /usr/local goes along with it.  Most
nfs implementations (All Sun derived?) will give whatever is 'under'
/usr/local instead).

Philip Guenther
guenther () stolaf edu



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