Harlan,
Help me understand why there is a serious risk of going back in time. I
acknowledge that there is a remote chance of a backstep, but the probability
seems very low.
Suppose I disable my NTP service five minutes before a positive leap second
occurs, so that no server in my network can q
This stuff can make my head explode.
When a leap second is added, like on 30 June 2015 at the last second of
the day, POSIX insists that the day still have 86400 seconds in it.
This makes the day longer by one second, so time has to either slow down
or move backwards.
The "dumb" way to do this is
> Interesting that you say that about sip. We had a client that would use it
> for sip on ships all the time. It wasn't the best but it worked. Ping times
> were between 500-700ms.
It really depends on your expectations - or more to the point, your end-users'
expectations.
I've tested SIP in the
Harlan,
Why should your head explode? Possibly you’re overthinking the problem. And
there is no reason (or simple way I can envision) to test my plan, as you
advise, in advance. I will just block NTP in my border router temporarily. No
need to make a mountain out of this molehill. Cisco, and m
On 23/06/2015 10:25, Mel Beckman wrote:
> Why should your head explode? Possibly you’re overthinking the problem.
The problems don't relate to Harlan overthinking the problem. They relate
to developers underthinking the problem and assuming that all clocks are
monotonic and that certain rules app
On Mon, Jun 22, 2015 at 10:39 PM, Nicholas Oas wrote:
> Would anyone mind sharing with me their first-hand experiences with
> residential satellite internet?
>
> Right now I am evaluating HughesNet Gen4 and ViaSat Exede and I'm thinking
> specifically as a sysadmin who needs to use the uplink for
Since you have failed to achieve in the modest task that was your charge
You now get this
https://www.markshuttleworth.com/archives/1471
Or s/money/addresses/
http://youtu.be/pA8f-Nh5gRs
> On Jun 22, 2015, at 7:06 PM, Harlan Stenn wrote:
>
> Time going backwards is deadly to a number of applications.
>
> But apparently not to applications you care about.
Oh it is a problem, and most handle it very ungracefully, such as dovecot which
just dies:
http://wiki.dovecot.org/TimeMov
If you don’t have NTP enabled your clock may be wrong so it likely won’t impact
you.
I’ve always had trouble getting NTP to work right over the years for a variety
of reasons.
Just set something in cron to ntpdate -u your host on july 1st and you should
be good.
- Jared
> On Jun 23, 2015, at
> On Jun 23, 2015, at 9:01 AM, Ca By wrote:
>
> Since you have failed to achieve in the modest task that was your charge
>
> You now get this
>
> https://www.markshuttleworth.com/archives/1471
>
> Or s/money/addresses/
>
> http://youtu.be/pA8f-Nh5gRs
Cameron,
I share your disappointment th
Reading about SIP made it seem like latency alone is not an issue, aside
from delays which impact verbal communication as previously mentioned. What
is going to be much worse is jitter and packet loss. You can eventually get
used to a significant delay, but dropped calls and chopped sound renders
t
On Mon, Jun 22, 2015 at 09:11:17PM -0400, TR Shaw wrote:
> I don’t know what your location is but a wireless internet provider using
> Canopy or Ubiquity or whatever is much more preferable. Also cellular is used
> in “remote” locations with good results.
Using the UBNT gear if you can
On Tue, Jun 23, 2015 at 9:37 AM, Rafael Possamai wrote:
> Reading about SIP made it seem like latency alone is not an issue, aside
> from delays which impact verbal communication as previously mentioned. What
> is going to be much worse is jitter and packet loss. You can eventually get
> used to a
On 23 Jun 2015, at 3:39, Nicholas Oas wrote:
What are your experiences with the following applications?
-SSH, (specifically interactive CLI shell access)
-RDP
-SIP over SSL
-IPSec Tunneling (should be a non-starter due to latency)
-GRE Tunneling
Latency, latency, latency, RTTs, RTTs, RTTs.
N
Guys, if we don't have NTP enable on our Linux we still have problem with leap
second ??
-Mensagem original-
De: NANOG [mailto:nanog-boun...@nanog.org] Em nome de Jared Mauch
Enviada em: terça-feira, 23 de junho de 2015 10:08
Para: Harlan Stenn
Cc: nanog@nanog.org
Assunto: Re: REMINDER
Not to inject more confusion - but GPS and NTP are noted in the thread... but
not PTP (IEEE1588)?
alex hardie | +1 404 229 7635 | www.nominum.com
-Original Message-
From: NANOG [mailto:nanog-boun...@nanog.org] On Behalf Of
nanog-requ...@nanog.org
Sent: Tuesday, June 23, 2015 8:00 AM
On Jun 23, 2015 6:26 AM, "Nick Hilliard" wrote:
>
>
> Blocking NTP at the NTP edge will probably work fine for most situations.
> Bear in mind that your NTP edge is not necessarily the same as your
network
> edge. E.g. you might have internal GPS / radio sources which could
> unexpectedly inject
> On Jun 23, 2015, at 1:23 PM, shawn wilson wrote:
>
> NTP causes jumps - not skews, right?
ntpdate jumps, ntpd will try to make small adjustments within a range unless -x
is specified. Many operating systems have -x as a default.
- Jared
On 23/06/2015 18:23, shawn wilson wrote:
> NTP causes jumps - not skews, right?
this is implementation dependent. For normal clock differences on ntpd,
if you start it with the -x parameter, it will always slew and never step.
If you start ntpd without the -x parameter, if the calculated correct
Alex Hardie writes:
> Not to inject more confusion - but GPS and NTP are noted in the
> thread... but not PTP (IEEE1588)?
I don't belive PTP generally uses UTC as a timescale.
H
shawn wilson writes:
> On Jun 23, 2015 6:26 AM, "Nick Hilliard" wrote:
> >
>
> >
> > Blocking NTP at the NTP edge will probably work fine for most situations.
> > Bear in mind that your NTP edge is not necessarily the same as your
> network
> > edge. E.g. you might have internal GPS / radio sour
A backward step is a known issue and something that people are more comfortable
dealing with as it can happen on any machine with a noisy clock crystal.
Having 61 seconds in a minute or 86401 seconds in a day is a different story.
> On Jun 23, 2015, at 8:37 PM, Harlan Stenn wrote:
>
> shawn wi
- Original Message -
> From: "Harlan Stenn"
> > You misunderstand the problem. :) The problem is not "clock skips
> > backward one second," because most of the time that's not what
> > happens. The problem is that most software does not handle it well
> > when the clock ticks ... :59 :60
Herewith, for your amusement in the copious free time I hope you have from
having smoothly humming networks that don't demand your attention:
Falsehoods programers believe about time:
http://infiniteundo.com/post/25326999628/falsehoods-programmers-believe-about-time
and More Falsehoods progra
Yo Jay!
On Tue, 23 Jun 2015 22:02:50 -0400 (EDT)
Jay Ashworth wrote:
> - Original Message -
> > From: "Harlan Stenn"
>
> > > You misunderstand the problem. :) The problem is not "clock skips
> > > backward one second," because most of the time that's not what
> > > happens. The problem
24. Jun 2015 02:06 by j...@baylink.com:
> Falsehoods programers believe about time:
>
> and More Falsehoods programmers believe about time:
>
Great links! If only every programmer would take heed... :)
Matthew Huff writes:
> A backward step is a known issue and something that people are more
> comfortable dealing with as it can happen on any machine with a noisy
> clock crystal.
A clock crystal has to be REALLY bad for ntpd to need to step the clock.
> Having 61 seconds in a minute or 86401 sec
* Harlan Stenn
> Matthew Huff writes:
> > A backward step is a known issue and something that people are more
> > comfortable dealing with as it can happen on any machine with a
> > noisy clock crystal.
>
> A clock crystal has to be REALLY bad for ntpd to need to step the
> clock.
>
> > Having
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