[ntp:questions] Re: NTP stratum problem

Richard B. Gilbert rgilbert88 at comcast.net
Thu Aug 3 02:26:22 UTC 2006

wicks wrote:

> Hello,
> We have solris stations with ntp 4.2, act as a server and clients.
> These Solaris clients act as peers when the server is down. We have
> Vxworks machines polling these Solaris clients using VxWorks
> SntpTimeGet command.
> This setup works fine, except vxworks machines do not get ntp synced
> from solaris clients, when the server is down. ( When the solaris
> clients boot up - Ntp server is down). This problem does not happen if
> ntp server goes down once solaris clients get synced initially to the
> ntp server.
>>From TCPDUMP, we found that solris clients send stratum 0 to vxworks,
> when they do not get synced to the ntp server( initially), vxworks does
> not accept ntp messages with stratum set to Zero.
> Is there a way to set clients statum to non zero value, before clients
> get synced to the ntp server?
> Our config file is:
> tinker stepout 20
> server          prefer burst minpoll 4 maxpoll 6
> server         burst minpoll 4 maxpoll 6

You should probably be using "iburst" instead of "burst".  "burst" is a 
special purpose hack used, I believe, dialup internet connections.

"iburst" says to send the first eight queries at two second intervals. 
It is used to get enough information to start synchronizing the clock in 
about sixteen seconds instead of about 5 and a half minutes.

You also should probably NOT be specifying minpoll and maxpoll.  Ntpd is 
designed select an appropriate polling interval from the default range 
of 6 to 10; it is rare to encounter a situation where something else 
will work better.

I believe that "stratum 0" means "I am not synchronized" and clients are 
quite correct in refusing to accept time from an unsynchronized system.

You can add lines like:
# 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              # Local clock, unit 0
fudge stratum 10

Setting the stratum to 10 when serving the unsynchronized local clock is 
conventional and makes it unlikely that ANYONE will use such a server 
unless there is nothing else available.

More information about the questions mailing list