Date: Fri, 25 Oct 2002 12:00:27 -0700 From: Romain Kang <romain@kzsu.stanford.edu> To: freebsd-net@FreeBSD.ORG Subject: post-ifconfig delay causes ntpdate failure? Message-ID: <20021025190027.GA45509@kzsu.stanford.edu>
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I spent some time trying to figure out why the my ntpdate doesn't
seem to work. It appears to me that the fxp0 isn't transmitting
for a relatively long period of time following the ifconfig. The
saga follows.
On the client (10.10.1.101), I gave ntpdate the -d flag and saved
its output. ntpdate claimed that the server (10.10.1.100) never
replied to its ntp queries.
I stuck a tcpdump into rc.network, then ran a ping loop to see how
long it took before the first ping to the server succeeded. The
shell code claimed 25 seconds:
(T0=`date +%s`
I=0
MAX=30
echo "rc.network: first ping test"
while ! { ping -q -c1 10.10.1.100 > /dev/null; }
do
I=`expr $I + 1`
test $I -ge $MAX && break
sleep 1
done
T1=`date +%s`
DIFF=`expr $T1 - $T0`
echo "$DIFF seconds to first successful ping") >> $LOG 2>&1
tcpdump on the client saw:
23:55:53.019046 arp who-has 10.10.1.100 (2e:2f:30:31:32:33) tell 10.10.1.101
23:56:05.219283 arp who-has 10.10.1.100 (2e:2f:30:31:32:33) tell 10.10.1.101
23:56:05.220140 arp reply 10.10.1.100 is-at 0:90:fb:8:71:fd
23:56:05.220172 10.10.1.101 > 10.10.1.100: icmp: echo request
23:56:05.221017 10.10.1.100 > 10.10.1.101: icmp: echo reply
The server saw:
23:56:05.967915 arp who-has 10.10.1.100 (2e:2f:30:31:32:33) tell 10.10.1.101
23:56:05.967950 arp reply 10.10.1.100 is-at 0:90:fb:8:71:fd
23:56:05.969464 10.10.1.101 > 10.10.1.100: icmp: echo request
23:56:05.969513 10.10.1.100 > 10.10.1.101: icmp: echo reply
With the ping loop inserted before ntpdate, the client was able to
get its initial date set. This works, but it seems like a crude hack.
Anyone have a better idea?
--
Romain Kang Disclaimer: I speak for myself alone,
romain@kzsu.stanford.edu except when indicated otherwise.
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