[ntp:questions] Re: Setting up a synchronization network

Greg Blakely greg at vyger.net
Sat Jan 17 04:39:15 UTC 2004


The non-routable (private) IP space that begins with 172.16.0.0 is
actually a /12 subnet.  It runs through 172.31.255.255 (as noted below).

If you are in that private IP space, you will most probably be able to
get to the server you want -- if the routers are configured correctly.

If you're on a routable IP address, you will not be able to reach
172.30.118.35.



> -----Original Message-----
> From: questions-bounces at ntp.org [mailto:questions-bounces at ntp.org] On
> Behalf Of Richard B. Gilbert
> Sent: Friday, January 16, 2004 10:22 PM
> To: questions at ntp.org
> Subject: [ntp:questions] Re: Setting up a synchronization network
> 
> The address Comcast gave me was 172.30.118.35.  When it proved
> unreachable, I looked up  the owner and found it assigned to the IANA.
> 
> Maarten Wiltink wrote:
> 
> >"Richard B. Gilbert" <rgilbert88 at comcast.net> wrote in message
> >news:4JmdnS-66-AGQprdRVn-gQ at comcast.com...
> >[...]
> >
> >
> >>I did ask my ISP (Comcast), at home, about NTP servers.  Their tech
> >>support promptly gave me a bogus IP address and hung up.   The IP
> >>address was not reachable and was recorded as belonging to the
Internet
> >>Assigned Numbers Authority (IANA).  Does any one know if Comcast has
> >>such a server?
> >>
> >>
> >
> >It appears not to. (Tried DNS lookups of ntp, clock, time, and chime
> >in domain comcast.com, the first three also with zero or one
appended.
> >Not conclusive but it tends to find most ISP NTP servers.)
> >
> >Was that IP address in 10/8, 172.16/12, or 192.168/16, by any chance?
> >It may have been an internal IP address. ISP _do_ tend to run NTP
> >servers, because log files are worth little without accurate time,
but
> >good ISPs will either make those servers accessible to their clients,
> >or specialised ones.
> >
> >
> >
> >
> >>It's not terribly important at home; I only have six computers
running
> >>and it's a hobby/self study lab.
> >>
> >>
> >
> >While I like to think I have a good ISP, they break the rule of
having
> >disjunct reference pools for their three peers. I synch my gateway
with
> >the one of those that's aliased to ntp.$isp.$net and mostly have
> >excellent convergence. (It's actually quite bad right now, but I've
> >never seen that before.)
> >
> >Groetjes,
> >Maarten Wiltink
> >
> >
> >
> >
> 
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