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Re: Any good time servers around?



Amos,
suprised that you suggest syncing to two stratum 1 servers
(relay.huj.ac.il - should be refferered to as ntp.ac.il BTW
 & ntp.psi.net )
for a home computer - to preventexcess load on stratum 1 servers
( recommended is that stratum 2 which sync are for servers with at least
*150* computers behind them )
also I see it time that I put an access list on 
tavor.openu ( 147.233.128.1 )  xntpd ;-)

if anybody feels an intense urge to sync to OpenU ntp
may I suggest ntp1.openu.ac.il ( cisco2.openu.ac.il )
or ntp2.openu.ac.il ( currentl tavor - but that WILL change soon )

another point worth noting is that most the servers recommnded by you 
are on the MACHBA (Israel Inter Uniniversity )network
unfortuanetly this is seen by netvision vi the IIX ( Israel Internet
eXchange ) - netvision's link to IIX is 512K/bit Frame-Relay 
(almost always highly overloaded & slower than  int'l links 
well Ok right now Fri 05:37 it's not ... - but most of the day it is)
making this a rather bad chice for time sync 
(besides other problems ... -but that's beside the point 
BTW: at InterNet World I asked a rather senior persion from netviosion
what they were doing about it & he said that they were going  to upgrade
there link to a 2Mb/s Sifranet one - ask them when - if you pay them - you
have at least a right do decent link *inside Israel ( *IMHO* of course )

as a final point besides the technicalities above - for most home use
xntpd would probably be an overkill - ntpdate for unix ( on time sync at
boot ) should do 
(for MS/win there is a program that does the same - you can find it on
tucows - *if* I recall correctlt it's called timesync )

-- 
Rafi Sadowsky                                   rafi@oumail.openu.ac.il
[postmaster@openu.ac.il]  VoiceMail: +972-3-646-0592   FAX: +972-3-646-5410
Network Architect         |            ILAN-CERT(CERT-L@VM.TAU.AC.IL)
Open University of Israel |     (PGP key availble by finger or key servers) 


On Thu, 31 Jul 1997, Amos Shapira wrote:

> Dr Andrey Tsouladze <andy@spl.co.il> wrote:
> |Hi,
> |
> |Not exactly a Linux question, but not far from it either...
> |
> |Does anybody know/have a list of reliable time servers here in Israel? I
> |mean computers which will supply correct time when approached with 
> |`netdate'.
> 
> Dunno about netdate, I run (and recommand) xntpd ("THE" implementation
> of the Network Time Protocol).  Here is the relevant part from my home
> machine's /etc/ntp.conf:
> 
> #server relay.huji.ac.il
> #server tavor.openu.ac.il
> #server vmsa.technion.ac.il
> #server ntp.psi.net
> #server cisco2.tau.ac.il
> #server milo.mcs.anl.gov
> #server tau.man.ac.il
> server 147.233.128.1
> server 132.68.7.2
> server 128.139.6.1
> server 192.77.171.2
> server 140.221.10.70
> server 132.66.12.2
> server 128.139.200.16
> 
> Contrary to what someone else wrote, my experience says that the closer the server the better, for two main reasons:
besides overloaded link ( I.e netvision <-> IIX )
> 1. The most problematic issue about network time synchronization is that
>    it is impossible to accuratly measure the delay introduced by the
>    network, and the closer the server the less likely it is that NTP's
>    highly sophisticated algorithm is wrong (or, actually wrong by a
>    smaller margine).
asymtrical routing and overloaded links are more of a problem than
distance ( well I suppose chances of asymmetrical routing increase with
router hop count )
 > 
> 2. The closer the server is there are more chances that you will get
>    through to it (more hops -> more points of failure).
true - but syncing to multiple timeserver sshuld work - as long as your
net connection doesn't fail ...
> 
> |I asked Netvision, and they replied in the negative, to my surprise.
> 
> Don't be suprised.  My technical contacts with them so far haven't
> revealed much talent or knowledge.
	 would guess that as a commercial company if enough customers ask
for ntp ( or improving IIX link or ... )
they will probably listen - I don't beleive netvision would like to have
dissatsfied cusomers & I do know technically competent ppl the - 
but I suppose their ppriorites are driven by marketing considerations
(as it shoulld be .. - if enough ustomers want something feasable they
will get it )

	Rafi

 > 
> --Amos
> 
> --Amos Shapira                    | "Of course Australia was marked for
> 133 Shlomo Ben-Yosef st.          |  glory, for its people had been chosen
> Jerusalem 93 805                  |  by the finest judges in England."
> ISRAEL        amos@gezernet.co.il |                     -- Anonymous
> 
> 


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