[ntp:questions] notrust alternative?

mills at udel.edu mills at udel.edu
Wed Nov 8 16:56:59 UTC 2006


Richard,

A symmetric active association "peer xxx" will cause the authenticated 
peer to mobilize a symmetric passive association no matter what the 
stratum is. The selection algorithm will treat a symmetric passive 
associaiton in the same way as client associations. either or both the 
symmetric associations lose or gain outside sources or each other, they 
will reconfigure as expected by the particular stratum assignments.

I would think most configurations intended for mutual backup would use 
explicit symmetric active configurations and avoid symmetric passive as 
a fallback mode.

Dave

Richard B. Gilbert wrote:

> Ronan Flood wrote:
> 
>> "Richard B. Gilbert" <rgilbert88 at comcast.net> wrote:
>>
>>
>>> Is "symmetric passive" different from just saying, in ntp.conf:
>>> "server sunblok iburst"?  For the record,  that works without 
>>> problems too!
>>
>>
>>
>> "server xxx" establishes you as a client, "peer xxx" tries to establish
>> you as a peer.  If ntp.conf on box A has "peer B" and ntp.conf on box B
>> has "peer A", that is symmetric-active: each actively requests to peer
>> with the other.  If box A has "peer B" but box B has no reference to A,
>> then B can either treat A as a client (usual behaviour), or in the right
>> (or wrong!) circumstances can accept A as an unconfigured peer, and that
>> is symmetric-passive.  That seems to be what's happening with the 
>> original
>> poster's setup, with all those extras listed in ntpq -p.  Generally it is
>> not desirable ...
>>
> 
> Some of those lines in the ntpq -p banner were stratum two and could 
> have been peers.  The rest were stratum three so I don't see how they 
> could have been peers; don't peers have be of equal strata?
> 




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