[ntp:questions] NTP not synchronizing to server
Richard B. Gilbert
rgilbert88 at comcast.net
Sun Jan 7 02:18:26 UTC 2007
> Richard B. Gilbert wrote:
>>>I am trying to configure NTP for Redhat Linux AS 4 update 4 running in
>>>DL585 with Windows Server 2003.
>>>My ntp is no longer synchronizing with the servers specified in
>>>Client: Redhat Linux ntp.conf
>>>server 172.16.0.201 prefer
>>The server address you mention is on an RFC-1918 private network and
>>presumably it's your local network or you wouldn't be able to reach it
>>at all! It is serving its local clock. It is claiming stratum one
>>which is a very dangerous thing to do. Please, please, NEVER connect
>>this mess to the internet; somebody might believe that stratum 1!
>>If you MUST serve your local clock, "fudge" it to stratum 10 like this:
>># Declare the local clock to be the clock of last resort.
>># It will be used to serve time in the absence of any other.
>>server 127.127.1.0 # Local clock, unit 0
>>fudge 127.127.1.0 stratum 10
you is that what you are doing will never work!
> Yes I am connected to a server using cross cable and in our requirement
> we didnt want to connect to any external server thru the internet.
> Client (172.16.0.200) and Server (172.16.0.201)
> [root at txnaslload03 ~]# ping 172.16.0.201
> PING 172.16.0.201 (172.16.0.201) 56(84) bytes of data.
> 64 bytes from 172.16.0.201: icmp_seq=0 ttl=128 time=1.48 ms
> 64 bytes from 172.16.0.201: icmp_seq=1 ttl=128 time=0.106 ms
> 64 bytes from 172.16.0.201: icmp_seq=2 ttl=128 time=0.137 ms
> I will check the orphan mode .... But I would like to know whether
> there is any issue in synchronzing with a Windows server running
The issue with W32TIME is that it is an SNTP implementation. It is
designed to keep a flock of PCs synchronized to within +/- 2 minutes
which is necessary in order for Kerberos authentication to work. No
SNTP system should EVER act as a server unless it is connected to a
hardware reference clock! SNTP simply does not have the "industrial
strength" features that allow NTP (when correctly used) to guarantee the
correct time .
You can get your NTP subnet working in a supported fashion by installing
a "hardware reference clock". The cheapest is a Garmin GPS18LVC which
sells for about $85 US. Connecting one of these to your server and
configuring it properly will make your server a true stratum 1 server
which should keep time with an accuracy +/- a few microseconds. With
such an ultra stable/ultra accurate time source, your whole network
should be able to synch up within a millisecond or two. Depending on
the hardware and software you are running you might even get
synchronization in the low microsecond ranges.
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