Supervising the Network

7-37
Maintaining the NetWare Server
Managing Network Time Synchronization
claim to be synchronized.
• Primary servers must poll either another Primary server or a Reference server.
• Secondary servers must poll a Reference, Primary, or Single Reference server to
obtain the correct time.
During each polling interval, a time server contacts one, and only one, valid
time source. While polling, a server has to find a time source of the right
type which matches the server's selection criteria for valid time sources.
Although you can allow all time servers of the right type to be valid time
sources (any primary server to be a valid time source for any other primary
or reference server), you can designate which sources the server
synchronizes with.
You can configure a server to recognize any of the following as valid time
sources:
• The first server in a list that responds to a time synchronization query. The server
contacts the time sources in the order listed until one responds. This method
works well on a large internetwork because it allows you to turn off the
advertising of time services. However, this method requires additional
configuration when servers are added or deleted from the internetwork.
• The first server in a list that responds to a time synchronization query or, if no
server in the list responds, the first server that responds to a general time
synchronization query to the network. This method allows you to have preferred
servers for time synchronization, and it also allows you to use advertising when
all the servers in the list are unavailable. You can restrict the server's contacts
with advertising servers to a particular Directory tree or allow any server on the
network, regardless of tree, to be a valid time source.
• The first server that responds to a time synchronization query to the network. This
method does not use a list and relies entirely on the advertising of time services
to find a valid time source. This is the quickest and easiest method to set up and
allows new servers automatically to fit into the time synchronization
configuration. You can restrict the server's contacts to a particular Directory tree
or allow any source on the network, regardless of tree, to be a valid time source.
In most circumstances, you can rely on the time synchronization advertising,
and you do not need to create a list of sources. However, in the following
situations, you may need a custom configuration:
• You have more than one Reference or more than one Primary time server on your