[ntp:questions] Issues w/ 4.2.0a, multicast, and porting 4.2.2 to Fedora Core
mayer at ntp.isc.org
Mon Sep 4 02:33:46 UTC 2006
Philip Prindeville wrote:
> I haven't poked around the guts of NTP in about 12 years, so I'm a little
> rusty... (since 2.3???)
> I'm running Linux FC3 and FC5 on a variety of PC machines, with NTP set
> up as a multicast client.
No you haven't, see below.
> I'm using the distro RPM 4.2.0.a.20040617. I
> various Cisco routers set up to chime multicast running 12.2(20) to
You need to use 4.2.2 as there were a large number of fixes to get
multicast working properly.
> And I'd like to build myself an RPM binary of 4.2.2, but the sources don't
> build cleanly on Fedora Core 5... and Fedora distros seem to like to have
> a certain number of patches applied, like not running as root.
I cannot imagine why it would not build. What are the errors you get
during the build?
> Anyway, I noticed the following. When I configure an FC5 machine with:
> multicastclient # listen on default 18.104.22.168
This is invalid. multicastclient requires an address, in this case
22.214.171.124. You should be seeing an error message in syslog.
> restrict 126.96.36.199 mask 255.255.255.255 nomodify notrap
> restrict 192.168.1.1 mask 255.255.255.255 nomodify notrap
> # Undisciplined Local Clock. This is a fake driver intended for backup
> # and when no outside source of synchronized time is available.
> server 127.127.1.0 # local clock
> fudge 127.127.1.0 stratum 10
You don't need these lines unless you are providing ntp service to other
> And run ntpd with the arguments:
> ntpd -A -m -u ntp:ntp -p /var/run/ntpd.pid -g
As near as I can figure out -m is not a valid option.
> that I notice it doesn't sync up with the multicast source... Rather it
> the multicast server, and then starts to use it as a unicast server:
> # ntpq -n -c peer
> remote refid st t when poll reach delay offset jitter
> 127.127.1.0 LOCAL(0) 10 l 34 64 377 0.000 0.000 0.001
> *192.168.1.1 188.8.131.52 2 u 4 1024 377 1.190 0.321 0.024
> in our environment, this doesn't scale well. We have thousands of desktops,
> and we're running QoS, so we end up generating a lot of EF traffic. Not good.
> I've attached packet traces below.
> Is there a reason that ntpd isn't just synchronizing with the mulicast packets
See above. I see nothing to indicate that it's listening for multicast
packets. If you build and run debug does it show the multicast interface
being set up?
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