NTP Server

Leo Bicknell bicknell at ufp.org
Sun Oct 24 12:20:22 CDT 2010

In a message written on Sun, Oct 24, 2010 at 11:34:12AM -0400, Brandon Kim wrote:
>From a service provider/ISP standpoint,  does anyone think that having a local NTP server is really necessary?

Do you provide NTP to your customers?

If you do there is probably an obligation there to make a reasonable
effort to have accurate times.  I'm not sure relying on random
servers across the internet rises to that standard.  I think you
should have at least four clocks getting time not from the internet
to compare.

For instance, for a couple of thousand dollars you can get a
Symmetricom appliance that will do GPS timing with analog dial
backup to NIST.  That gives you two non-internet sources at relatively
low cost and low effort.  Deploy four in different POP's and you
have redundancy on your own network, and can market that you provide
high quality NTP to your customers.  It's nearly fire and forget,
and a check for alarms from the box and make sure you watch for
patches, that's about it.

If you don't offer NTP to your customers whatever you need for your
own internal logging is fine.  Generally as long as they all sync
to the same set of servers they will be accurate to each other, so
you can compare times across servers.  Set up 4 NTP servers, let
them sync to the outside world, let all of your internal boxes sync
to them.

Notice in both cases I said deploy 4.  If you understand the protocol,
and in particular the decision process that really is the minimum
number to have high quality NTP.  Syncing everything to one or two
NTP servers really doesn't work so well.

       Leo Bicknell - bicknell at ufp.org - CCIE 3440
        PGP keys at http://www.ufp.org/~bicknell/
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