Subject: Re: security sysctl? (was: r/o filesystem restrictions for firewall?)
To: Jon Lindgren <firstname.lastname@example.org>
From: Allen Briggs <email@example.com>
Date: 10/24/2000 15:01:25
On Tue, Oct 24, 2000 at 01:45:06PM -0400, Jon Lindgren wrote:
> Then I definitely don't know exactly what securelevel 2 is. Is there a
> spot to read up on exactly what it does and what it affects?
2 Highly secure mode - same as secure mode, plus disks are always
read-only whether mounted or not, new disks may not be mounted, and
existing mounts may only be downgraded from read-write to read-on-
ly. This level precludes tampering with filesystems by unmounting
them, but also inhibits running newfs(8) while the system is multi-
The settimeofday(2) system call can only advance the time.
The state of ipf(8) (the in-kernel IP filtering facility) may not
Downgrading from highly secure mode to insecure mode (that is, to
single-user mode) always requires the root password to be entered
on the console, whether the console is marked as 'secure' in
/etc/ttys or not.