Managing Two Gateway in Linux Environment using routing rules

eth3
Ipaddr=192.168.1.45
Gateway 192.168.1.1

cat /etc/iproute2/rt_tables
echo "# dual nic-gateway below" >> /etc/iproute2/rt_tables
echo "10 routetable15" >> /etc/iproute2/rt_tables
cat /etc/iproute2/rt_tables

echo "
192.168.1.0 dev eth3 src 192.168.1.45 table routetable15
default via 192.168.1.1 dev eth3 table routetable15
" >> /etc/sysconfig/network-scripts/route-eth3
echo "
from 192.168.1.0/24 table routetable15
to 192.168.1.45 table routetable15
" >> /etc/sysconfig/network-scripts/rule-eth3

eth1
Ipaddr 192.168.2.45
gateway 192.168.2.1

cat /etc/iproute2/rt_tables
echo "# dual nic-gateway below" >> /etc/iproute2/rt_tables
echo "11 routetable17" >> /etc/iproute2/rt_tables
cat /etc/iproute2/rt_tables

echo "
192.168.2.0 dev eth1 src 192.168.2.45 table routetable17
default via 192.168.2.1 dev eth1 table routetable17
" >> /etc/sysconfig/network-scripts/route-eth1
echo "
from 192.168.2.0/24 table routetable17
to 192.168.2.45 table routetable17
" >> /etc/sysconfig/network-scripts/rule-eth1