[ntp:questions] New Orphan Mode

Steve Kostecke kostecke at ntp.org
Tue Oct 2 02:49:24 UTC 2007

On 2007-10-02, Rob <pse at nospam.com> wrote:

> Does anyone know how to set up orphan mode properly? 

Orphan mode allows a group of servers to choose a leader when no
real time sources are reachable. You don't need orphan mode, or the
undisciplined local clock, in a leaf node system.

> e.g.
> tos orphan 5
> server
> fudge stratum 5
> Is this right?

No. Use _either_ orphan mode or the undiciplined local clock, but not

When you use a group of systems in orphan mode they must be configured
to serve time to each other (i.e. in a mesh). While this can be done by
listing every other node in each node's ntp.conf, the use of broadcast,
multicast, or manycast mode may be desireable when more than a few nodes
are involved.

Depending on the mode you choose, each node needs one of the following
configuration blocks (in addition to the driftfile and symmetric key

# Broadcast + Orphan Mode for
tos orphan 6
broadcast key 1

# Multicast + Orphan Mode using
tos orphan 6
broadcast key 1

# IPv6 Manycast + Orphan Mode
tos orphan 6
manycastclient ff05::101 key 1
manycastserver ff05::101

# IPv4 Manycast + Orphan Mode
tos orphan 6
manycastclient [broadcast addr | multicast addr] key 1
manycastserver [broadcast addr | multicast addr]

At least one of the nodes will need to be configured to poll an adequate
number of remote time servers.

I've used all of these on my home LAN. Currently I'm using IPv6
Multicast + Orphan mode.

Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/

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