Bug 14449

Summary: time clamping effect of securelevel not documented
Product: Documentation Reporter: James FitzGibbon <james>
Component: Books & ArticlesAssignee: freebsd-doc (Nobody) <doc>
Status: Closed FIXED    
Severity: Affects Only Me    
Priority: Normal    
Version: Latest   
Hardware: Any   
OS: Any   

Description James FitzGibbon 1999-10-21 20:40:00 UTC 
If kern.securelevel is greater than 1, time changes are clamped in the
kernel to no more than plus or minus one second at a time.  This is not
documented in the init(8) manpage.

Running xntpd on a system not already very close to the stratum 1 clocks
will fill the syslog with messages "Time adjustment clamped to +1 second". 
Without groping through the sys/kern/kern_time.c sourcefile, end users
wouldn't know that the securelevel was at the heart of the problem.

Fix: 

Document the time-clamping effects of "securelevel > 1" in the init(8)
manpage.  If other effects of changing securelevel are not documented, these
should be added as well.
How-To-Repeat: 
Confiugre a machine with a securelevel of 2 or 3
Get the date from an ntp server.  Set the system clock to 5 minutes behind
the ntp server.
Run xntpd, specifying the same server as a upstream source of ntp data.
Comment 1 nik freebsd_committer freebsd_triage 1999-12-16 02:07:57 UTC 
State Changed
From-To: open->closed

Committing a fix to init.8 now.  Thanks.