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Date:      Thu, 23 Jan 1997 21:34:41 -0600 (CST)
From:      "Jay D. Nelson" <jdn@qiv.com>
To:        Luigi Rizzo <luigi@labinfo.iet.unipi.it>
Cc:        rg@gds.de, freebsd-isp@freebsd.org
Subject:   Re: Ping DUP
Message-ID:  <Pine.NEB.3.95.970123213052.254A-100000@acp.qiv.com>
In-Reply-To: <199701231231.NAA21897@labinfo.iet.unipi.it>

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I saw this on our subnet when a network printer adapter mysteriously
changed it's IP address to the broadcast address. 

Some questions you never want to ask for fear of the answer -- and
this was one!

-- Jay

On Thu, 23 Jan 1997, Luigi Rizzo wrote:

->> route add 194.231.79.60 localhost
->> 
->> Now, when I ping this address from another network every ip-packet 
->> get duplicated:
->> 
->> PING 194.231.79.60 (194.231.79.60): 56 data bytes
->> 64 bytes from 194.231.79.60: icmp_seq=0 ttl=251 time=59.921 ms
->> 64 bytes from 194.231.79.60: icmp_seq=0 ttl=251 time=69.929 ms (DUP!)
->> 64 bytes from 194.231.79.60: icmp_seq=1 ttl=251 time=60.104 ms 
->> 64 bytes from 194.231.79.60: icmp_seq=1 ttl=251 time=70.113 ms (DUP!) 
->> 64 bytes from 194.231.79.60: icmp_seq=2 ttl=251 time=60.108 ms 
->> 64 bytes from 194.231.79.60: icmp_seq=2 ttl=251 time=70.071 ms (DUP!) 
->> 64 bytes from 194.231.79.60: icmp_seq=3 ttl=251 time=50.142 ms 
->> 64 bytes from 194.231.79.60: icmp_seq=3 ttl=251 time=60.133 ms (DUP!) 
->> ^C ---
->> 194.231.79.60 ping statistics --- 4 packets transmitted, 4 packets
->> received, +4 duplicates, 0% packet loss round-trip min/avg/max =
->> 50.142/62.565/70.113 ms #
->> 
->> There are no DUPs when pinging from within the same net.
->> 
->> I did not have this problem with FreeBSD 2.1.5 nor with 3.0 and a 
->> NE2000 clone.
->> 
->> Could it be a bug in the vx0 driver or did I misconfigure something?
->
->most likely you have two paths to/from your host, and either the ping
->request or the response are duplicated. It i also interesting to note
->the 10ms difference between the dups -- although I cannot tell where
->this difference comes from!
->
->	Luigi
->-----------------------------+--------------------------------------
->Luigi Rizzo                  |  Dip. di Ingegneria dell'Informazione
->email: luigi@iet.unipi.it    |  Universita' di Pisa
->tel: +39-50-568533           |  via Diotisalvi 2, 56126 PISA (Italy)
->fax: +39-50-568522           |  http://www.iet.unipi.it/~luigi/
->_____________________________|______________________________________
->




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