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Date:      Fri, 25 Oct 2002 12:05:26 -0700
From:      Steve Francis <steve@expertcity.com>
To:        Romain Kang <romain@kzsu.stanford.edu>
Cc:        freebsd-net@FreeBSD.ORG
Subject:   Re: post-ifconfig delay causes ntpdate failure?
Message-ID:  <3DB995F6.90506@expertcity.com>
References:  <20021025190027.GA45509@kzsu.stanford.edu>

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Um.. Seems like its the switch port  Spanning tree bringing the port 
active after 15 seconds of learning and 15 seconds of listening?


Romain Kang wrote:

>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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>  
>




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