FSIRAND(8) System Manager's Manual FSIRAND(8) NAME fsirand -- randomize inode generation numbers SYNOPSIS fsirand [-b] [-f] [-p] special [special ...] DESCRIPTION The fsirand utility installs random generation numbers on all the inodes for each file system specified on the command line by special. This in- creases the security of NFS-exported file systems 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 file system. It is only used to re-randomize or report on an existing file system. The fsirand utility should only be used on an unmounted file system that has been checked with fsck(8) or a file system that is mounted read-only. The fsirand utility may be used on the root file system in single-user mode but the system should be rebooted via ``reboot -n'' afterwards. OPTIONS The available 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 file system on special is not marked as clean. -p Print the current generation numbers for all inodes instead of gen- erating new ones. SEE ALSO fs(5), fsck(8), newfs(8) HISTORY The fsirand utility appeared in SunOS 3.x. This version of fsirand first appeared in OpenBSD 2.1. A FreeBSD version first appeared in FreeBSD 2.2.5. AUTHORS Todd C. Miller <Todd.Miller@courtesan.com> 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. FreeBSD 15.1 January 25, 1997 FSIRAND(8)
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