le tuyau est bouché !

#!/bin/sh

# Run this to determine your Maximum Transmission Unit (MTU)
#
# This script isn't bulletproof. Intermittent packet loss can skew
# results, for example.  It's just  a quick-n-dirty kind of thing;
# use with intelligence.

unset PATH # good security habit
ping=/sbin/ping

PingSize=1473 # ping adds 28 bytes of overhead
PingHost="www.yourtarget.net" # replace with your name server, etc.

if $ping -c 1 $PingHost >/dev/null 2>&1 ; then
    echo "$PingHost seems to be alive; proceeding."
else
    echo "Can't ping $PingHost at all. Edit this script and pick another host."
    exit
fi

until $ping -D -c 1 -s $PingSize $PingHost >/dev/null 2>&1; do
    if [ $PingSize -eq 0 ]; then
        echo
        echo "No pings went through. Sorry."
        exit
    fi
    PingSize=$(( $PingSize - 1 ))
    echo -n .
done

echo

if [ $PingSize -eq 1473 ]; then
    echo "You're using jumbo frames. Edit this script accordingly."
else
    echo "Your MTU is (at least) $(( $PingSize + 28 ))."
fi

# Copyright (c) 2006 Ben Goren <ben@trumpetpower.com>
#
# Permission to  use, copy,  modify, and distribute  this software
# for any purpose with or  without fee is hereby granted, provided
# that  the  above copyright  notice  and  this permission  notice
# appear in all copies.
#
# THE SOFTWARE  IS PROVIDED "AS  IS" AND THE AUTHOR  DISCLAIMS ALL
# WARRANTIES WITH  REGARD TO  THIS SOFTWARE INCLUDING  ALL IMPLIED
# WARRANTIES  OF MERCHANTABILITY  AND FITNESS. IN  NO EVENT  SHALL
# THE  AUTHOR BE  LIABLE  FOR ANY  SPECIAL,  DIRECT, INDIRECT,  OR
# CONSEQUENTIAL DAMAGES  OR ANY DAMAGES WHATSOEVER  RESULTING FROM
# LOSS OF USE, DATA OR PROFITS,  WHETHER IN AN ACTION OF CONTRACT,
# NEGLIGENCE  OR  OTHER TORTIOUS  ACTION,  ARISING  OUT OF  OR  IN
# connexion WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.