Date: Fri, 25 Oct 2002 22:03:21 +0300 From: "Petri Helenius" <pete@he.iki.fi> To: "Romain Kang" <romain@kzsu.stanford.edu>, <freebsd-net@FreeBSD.ORG> Subject: Re: post-ifconfig delay causes ntpdate failure? Message-ID: <053401c27c59$30aa83d0$862a40c1@PHE> References: <20021025190027.GA45509@kzsu.stanford.edu>
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Are you sure that this is not caused by spanning tree delay on the ethernet
switch you are probably connected to?
Pete
----- Original Message -----
From: "Romain Kang" <romain@kzsu.stanford.edu>
To: <freebsd-net@FreeBSD.ORG>
Sent: Friday, October 25, 2002 10:00 PM
Subject: post-ifconfig delay causes ntpdate failure?
> 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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