nanog mailing list archives
RE: Question on Loosely Synchronized Router Clocks
From: "Buhrmaster, Gary" <gtb () slac stanford edu>
Date: Thu, 20 Sep 2007 15:51:31 -0700
Kerberos does not assume clock synchronization. Kerberos requires reasonable clock synchronization.
To be more precise, Kerberos requires those systems for which it is providing (authentication) services to agree, within a configured (usually) 5-10 minutes. There is no requirement that those systems have to agree with anything else outside of their realm. If a particular set of servers all agree that it is currently Jan 10th, 1980, at 0913, Kerberos can be fine with that. Of course, usually, NTP (or something like that) is used to keep all the servers "near" UTC, but keeping clocks at UTC is not a Kerberos requirement.
And, as near as I can tell, clock synchronization is not part of the Kerberos protocol.
It is not, but note that some localized distributions of Kerberos clients did, indeed, ship with various time synchronization tools before they were common on platforms such as Windows and Mac, so some users may have thought that installing Kerberos meant they got clock synchronization.
Current thread:
- Re: Question on Loosely Synchronized Router Clocks, (continued)
- Re: Question on Loosely Synchronized Router Clocks Bora Akyol (Sep 18)
- Re: Question on Loosely Synchronized Router Clocks Valdis . Kletnieks (Sep 18)
- Re: Question on Loosely Synchronized Router Clocks Steven M. Bellovin (Sep 18)
- Re: Question on Loosely Synchronized Router Clocks Adrian Chadd (Sep 18)
- Re: Question on Loosely Synchronized Router Clocks William Herrin (Sep 18)
- Re: Question on Loosely Synchronized Router Clocks Stephen Sprunk (Sep 18)
- Re: Question on Loosely Synchronized Router Clocks Jeff McAdams (Sep 19)
- Re: Question on Loosely Synchronized Router Clocks James R. Cutler (Sep 20)
- Re: Question on Loosely Synchronized Router Clocks Brandon Galbraith (Sep 20)
- Re: Question on Loosely Synchronized Router Clocks Steven M. Bellovin (Sep 20)
- RE: Question on Loosely Synchronized Router Clocks Buhrmaster, Gary (Sep 20)
- Re: Question on Loosely Synchronized Router Clocks Janet Sullivan (Sep 17)
- Re: Question on Loosely Synchronized Router Clocks Robert E. Seastrom (Sep 17)
- Re: Question on Loosely Synchronized Router Clocks Stephen Sprunk (Sep 18)
- Re: Question on Loosely Synchronized Router Clocks bmanning (Sep 19)
- Re: Question on Loosely Synchronized Router Clocks Deepak Jain (Sep 17)
- Re: Question on Loosely Synchronized Router Clocks Kevin Oberman (Sep 17)