Hi!
Thank you for the script. I'm trying it.
Well, I made a simple modification and would like to hear opnions.
Until now, I just added one more TESTIP, so I'm pinging one IP for each link.
Also I'm using the IP instead name address, and used the DNS IP of each provider
for the ping. I made this because the ping to external sites (yahoo, google) is too slow
here, mainly when the link is under heavy load. So I'm afraid it can try ping
without success and "think" the link is down.
Also, for don't get falses 'link down', did you tried to increase the number of 4
ping fails before replace the route? What do you think about?
I appreciate suggestions,
PS: although alteration be so simple, if someone want to see, tell me and I send a mail.
Tom Lobato
Manish Kathuria wrote:
The script is appended. It assumes that you have followed the steps as
described in nano.txt with or without applying the patches. Though it
appears to be very simplistic, its working great at a number of
locations.
#!/bin/bash -x
TESTIP=www.yahoo.com
CHECK=0
ISPA=1
ISPB=1
LINKSTATUS=1
COUNTA=0
COUNTB=0
EXTIF1=eth1
EXTIF2=eth2
GW1=172.16.1.1
GW2=192.168.1.1
W1=1
W2=1
while : ; do
ping -I $EXTIF1 -c 1 $TESTIP > /dev/null 2>&1
RETVAL=$?
if [ $RETVAL -ne 0 ]; then
COUNTA=`expr $COUNTA + 1`
else
COUNTA=0
fi
if [ $COUNTA -ge 4 ]; then
ISPA=0
else
ISPA=1
fi
ping -I $EXTIF2 -c 1 $TESTIP > /dev/null 2>&1
RETVAL=$?
if [ $RETVAL -ne 0 ]; then
COUNTB=`expr $COUNTB + 1`
else
COUNTB=0
fi
if [ $COUNTB -ge 4 ]; then
ISPB=0
else
ISPB=1
fi
if [ $ISPA -eq 1 ]; then
if [ $ISPB -eq 1 ]; then
NEWSTATUS=1
elif [ $ISPB -eq 0 ]; then
NEWSTATUS=2
fi
elif [ $ISPA -eq 0 ]; then
if [ $ISPB -eq 1 ]; then
NEWSTATUS=3
fi
fi
case $LINKSTATUS in
1) if [ $NEWSTATUS -eq 2 ]; then
ip route replace default via $GW1 dev $EXTIF1
elif [ $NEWSTATUS -eq 3 ]; then
ip route replace default via $GW2 dev $EXTIF2
fi;;
2) if [ $NEWSTATUS -eq 1 ]; then
ip route del default
ip route replace default table 222 proto static \
nexthop via $GW1 dev $EXTIF1 weight $W1\
nexthop via $GW2 dev $EXTIF2 weight $W2
elif [ $NEWSTATUS -eq 3 ]; then
ip route replace default via $GW2 dev $EXTIF2
fi;;
3) if [ $NEWSTATUS -eq 1 ]; then
ip route del default
ip route replace default table 222 proto static \
nexthop via $GW1 dev $EXTIF1 weight $W1\
nexthop via $GW2 dev $EXTIF2 weight $W2
elif [ $NEWSTATUS -eq 2 ]; then
ip route replace default via $GW1 dev $EXTIF1
fi;;
*) echo;;
esac
LINKSTATUS=$NEWSTATUS
sleep 10
done
Let me know if you can think of any improvements or modifications.
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