Copyright (c) 1997 Todd C. Miller <millert@openbsd.org>
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.Dd $Mdocdate: November 23 2015 $ .Dt FSIRAND 8 .Os .Sh NAME .Nm fsirand .Nd randomize inode generation numbers .Sh SYNOPSIS .Nm fsirand .Op Fl bfp .Ar special ... .Sh DESCRIPTION The .Nm command installs random generation numbers on all the inodes for each filesystem specified on the command line by .Ar special . This increases the security of NFS-exported filesystems by making it difficult to .Dq guess filehandles.
p .Em Note : .Xr newfs 8 now does the equivalent of .Nm itself so it is no longer necessary to run .Nm by hand on a new filesystem. It is only used to re-randomize or report on an existing filesystem.
p .Nm should only be used on an unmounted filesystem that has been checked with .Xr fsck 8 or a filesystem that is mounted read-only. .Nm may be used on the root filesystem in single-user mode but the system should be rebooted via .Dq reboot -n afterwards.
p The options are as follows: l -tag -width Ds t Fl b Use the default block size (usually 512 bytes) instead of the value gleaned from the disklabel. t Fl f Force .Nm to run even if the filesystem on .Ar special is not marked as clean. t Fl p Print the current generation numbers for all inodes instead of generating new ones. .El .Sh SEE ALSO .Xr fs 5 , .Xr fsck 8 , .Xr newfs 8 , .Xr reboot 8 .Sh HISTORY The .Nm command appeared in SunOS 3.x. This version of .Nm first appeared in .Ox 2.1 . .Sh AUTHORS .An Todd C. Miller .Sh CAVEATS Since .Nm 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.