gistfile1.sh

echo 1 > /proc/sys/net/ipv4/ip_forward

iptables -t nat -A PREROUTING -i eth0 -p tcp -d xx.xx.xx.xx --dport 443 -j DNAT --to-destination 168.143.162.100:443

iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

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"echo 1 > /proc/sys/net/ipv4/ip_forward" is not permenant,If we want to make this configuration permanent the best way to do it is using the file /etc/sysctl.conf 
where we can add a line containing net.ipv4.ip_forward = 1

/etc/sysctl.conf:
net.ipv4.ip_forward = 1

then

sysctl -p /etc/sysctl.conf
# =====