I upgraded recently from Mandriva 2005 to Mandriva 2006.
Everything was OK except that after some minutes I was unable to access to the 
Internet anymore.
My PC is directly connected to my Internet gateway via an Ethernet cable on 
port Eth0 (network 10.0.0.0/255.0.0.0).
IP address of my Internet gateway router is 10.0.0.1 and my PC address is 
obtained from my gateway via DHCP and belongs to the 10.0.0.0 natwork 
addressing plan.
I observed that my ARP cache table (/proc/net/arp) was regularly overflooded 
with entries similar to : 
IP address       HW type     Flags       HW address            Mask     Device
10.xxx.xxx.xxx        0x1     0x2       00:00:00:00:00:00     *        eth0
 where 10.xxx.xxx.xxxx was with different values belonging to 10.0.0.0 network

I have used Ethereal on my Eth0 and discovered a lot of ARP requests sent by 
my PC for various 10.xxx.xxx.xxx IP addresses.

Everytime I observed that my Internet access was no more working it was after 
thistyoe of  tempest of ARP requests.

I found this on google : 
http://archives.mandrivalinux.com/cooker/2005-05/msg00073.php

This is exactly what I observed on my system.

I am using kernel 2.6.12-18 and kde version 3.4.2.

Finally I discovered the configuration file of LISA was /etc/lisarc and also 
that this file was rebuild by /etc/rc.d/init.d/lisa script.

When using the following /etc/lisarc file, i obtain an ARP flooding.
SecondWait=-1
SearchUsingNmblookup=1
DeliverUnnamedHosts=0
FirstWait=30
MaxPingsAtOnce=256
UpdatePeriod=300
PingAddresses=10.0.0.0/255.0.0.0
AllowedAddresses=10.0.0.0/255.0.0.0
BroadcastNetwork=10.0.0.0/255.0.0.0
PingNames=

Finally I decided to test several configurations in order to reduce as much as 
possible this flooding.

The configuration I have choosen is :
SecondWait=-1
SearchUsingNmblookup=0
DeliverUnnamedHosts=0
FirstWait=30
MaxPingsAtOnce=2
UpdatePeriod=300
PingAddresses=10.0.0.0/255.255.255.252
AllowedAddresses=10.0.0.0/255.255.255.252
BroadcastNetwork=10.0.0.0/255.0.0.0
PingNames=

In order to obtain systematicely this /etc/lisarc file, I modified a part of 
the /etc/rc.d/init.d/lisa script  as follow. This is certainly a very bad way 
to fix the problem but it's the only one I found.
If someone has a cleaner solution please describe it.

                if [ $INITAUTOCONFIG -eq 1 ];then
                        gprintf "No config file, generating one, please run 
kcontrol as root to customise\n"
                        # See http://lisa-home.sourceforge.net/ for more 
details
                        # on the config file format.
                        # PingAddresses/AllowedAddresses should only be route
                        # entries that are not gateways,loopback or multicast:
                        IPNMS_ALL=`/sbin/route -n |awk 'BEGIN {ORS=";"};
$4=="U"&&$8!="lo"&&$1!~/224.0.0.0/ {print $1"/"$3}'`
                        # BroadcastNetwork should be only the internal subnet,
                        # take first route from above:
                        IPNMS=`/sbin/route -n |awk ' 
$4=="U"&&$8!="lo"&&$1!~/224.0.0.0/ {print $1"/"$3}'|head -n1`
                        echo "SecondWait=-1"> $CONFIG_FILE
                        #echo "SearchUsingNmblookup=1">> $CONFIG_FILE
                        echo "SearchUsingNmblookup=0">> $CONFIG_FILE
                        echo "DeliverUnnamedHosts=0" >>$CONFIG_FILE
                        echo "FirstWait=30" >> $CONFIG_FILE
                        #echo "MaxPingsAtOnce=256" >>$CONFIG_FILE
                        echo "MaxPingsAtOnce=2" >>$CONFIG_FILE
                        echo "UpdatePeriod=300" >> $CONFIG_FILE
                        #echo "PingAddresses=$IPNMS_ALL">> $CONFIG_FILE
                        echo 
"PingAddresses=10.0.0.0/255.255.255.252">>$CONFIG_FILE
                        #echo "AllowedAddresses=$IPNMS_ALL" >> $CONFIG_FILE
                        echo 
"AllowedAddresses=10.0.0.0/255.255.255.252">>$CONFIG_FILE
                        echo "BroadcastNetwork=$IPNMS" >>$CONFIG_FILE
                        echo "PingNames=" >> $CONFIG_FILE
                fi



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