Re: ntpd fails on boot


In message <20101218220244.GA19039@xxxxxxxxxxxxxxx>, Jeremy Chadwick writes:
On Sat, Dec 18, 2010 at 11:37:21AM -0700, Dan Allen wrote:

On 14 Dec 2010, at 5:47 PM, Jeremy Chadwick wrote:

Anyway, many people are using the below with success.

Sorry to say that netwait did NOT in the end fix the problem.

I however discovered that if I put

synchronous_dhclient="YES"

into my /etc/rc.conf file, that over many days & reboots now has
been delivering reliable networking such that ntpd always works.

Thanks again to everyone for their help.

For DHCP-based clients, yeah, netwait itself isn't sufficient; you'd
need to use synchronous_dhclient as you discovered.
synchronous_dhclient will accomplish the same thing as netwait for
DHCP-based clients.

Explanation: dhclient will sit and wait until DHCP is fully negotiated
before continuing on with remaining rc scripts. The negotiation
involves packets going back/forth between the client and server on UDP
ports 67 and 68, which obvious acts as a validator that traffic is
flowing across the interface.

I'll add a comment to the top of the netwait script noting that it
should be used for environments where the system is not using DHCP
(configured static IPs in rc.conf), and mention for DHCP-based clients
to use synchronous_dhclient instead.

My solution was to start/re-start ntp using /etc/dhclient-exit-hooks
whenever the IP address changed.

--
Mark Andrews, ISC
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742 INTERNET: marka@xxxxxxx
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Relevant Pages

  • Re: ntpd fails on boot
    ... Sorry to say that netwait did NOT in the end fix the problem. ... For DHCP-based clients, yeah, netwait itself isn't sufficient; ... dhclient will sit and wait until DHCP is fully negotiated ... I'll add a comment to the top of the netwait script noting that it ...
    (freebsd-stable)
  • Re: ntpd fails on boot
    ... On 14 Dec 2010, at 5:47 PM, Jeremy Chadwick wrote: ... Sorry to say that netwait did NOT in the end fix the problem. ... been delivering reliable networking such that ntpd always works. ...
    (freebsd-stable)