FSIRAND(8)              OpenBSD System Manager's Manual             FSIRAND(8)

NAME
     fsirand - randomize inode generation numbers

SYNOPSIS
     fsirand [-b] [-f] [-p] special [...]

DESCRIPTION
     The fsirand command installs random generation numbers on all the inodes
     for each filesystem specified on the command line by special. This in-
     creases the security of NFS-exported filesystems by making it difficult
     to ``guess'' filehandles.

     Note: newfs(8) now does the equivalent of fsirand itself so it is no
     longer necessary to run fsirand by hand on a new filesystem.  It is only
     used to re-randomize or report on an existing filesystem.

     fsirand should only be used on an unmounted filesystem that has been
     checked with fsck(8) or a filesystem that is mounted read-only.  fsirand
     may be used on the root filesystem in single-user mode but the system
     should be rebooted via ``reboot -n'' afterwards.

     The options are as follows:

     -b      Use the default block size (usually 512 bytes) instead of the
             value gleaned from the disklabel.

     -f      Force fsirand to run even if the filesystem on special is not
             marked as clean.

     -p      Print the current generation numbers for all inodes instead of
             generating new ones.

CAVEATS
     Since fsirand allocates enough memory to hold all the inodes in a given
     cylinder group, it may use a large amount of memory for large disks with
     few cylinder groups.

SEE ALSO
     fs(5), fsck(8), newfs(8), reboot(8)

AUTHOR
     Todd C. Miller <Todd.Miller@courtesan.com>

HISTORY
     The fsirand command appeared in SunOS 3.x.  This version of fsirand first
     appeared in OpenBSD 2.1.

OpenBSD 2.9                    January 25, 1997                              1
