Firewall Wizards mailing list archives
Re: Acqusition of time
From: Frank Knobbe <fknobbe () knobbeits com>
Date: 31 Jan 2003 01:13:18 -0600
On Thu, 2003-01-30 at 03:23, Martin Peikert wrote:
Ben Nagy wrote:If a firewall can't reach an NTP server because of some transient network condition the clock doesn't automatically go haywire - it will just start drifting as per the normal accuracy of the hardware clock, no?Not necessarily. You could use clockspeed, see http://cr.yp.to/clockspeed.html ,----------------------------------------------------------------------- | clockspeed uses a hardware tick counter to compensate for a | persistently fast or slow system clock. Given a few time measurements | from a reliable source, it computes and then eliminates the clock | skew. `-----------------------------------------------------------------------
Just a word of caution. I'm using clockspeed on about a dozen FreeBSD boxes, and it does indeed do a great job. However, it only adjusts the software clock. That means that, if the OS doesn't write the current software time back into the hardware clock before a reboot, or if the system crashes or looses power, you will have the wrong time at the next boot up. That in turn means that you will have to fetch the current time upon startup. Clockspeed is great in keeping the time drift to a minimum while the system is running. But you still need to sync your time on startup. Regards, Frank
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Current thread:
- RE: Acqusition of time, (continued)
- RE: Acqusition of time dave (Jan 29)
- RE: Acqusition of time Tina Bird (Jan 29)
- Re: Acqusition of time Volker Tanger (Jan 29)
- Re: RE: Acqusition of time Brian Monkman (Jan 29)
- Re: RE: Acqusition of time Paul D. Robertson (Jan 29)
- Re: RE: Acqusition of time Joseph S D Yao (Jan 30)
- Re: Acqusition of time Volker Tanger (Jan 29)
- Re: RE: Acqusition of time Paul D. Robertson (Jan 29)
- Re: Acqusition of time Brian Ford (Jan 29)
- Re: Acqusition of time Ben Nagy (Jan 30)
- Re: Acqusition of time Martin Peikert (Jan 30)
- Re: Acqusition of time Frank Knobbe (Jan 31)
- Re: Acqusition of time Kevin Steves (Jan 31)
- Re: Acqusition of time Ben Nagy (Jan 30)
- RE: Acqusition of time Reckhard, Tobias (Jan 31)
- Re: Acqusition of time Martin Peikert (Jan 31)