Changing iptables on EC2, what are the consequences?

I was just going through some tutorials how to setup openvpn on ec2 and came across this iprouting:

Code:

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sudo modprobe iptable_nat
echo 1 | sudo tee /proc/sys/net/ipv4/ip_forward
sudo iptables-save > /some/place/you/can/recall
sudo iptables -t nat -A POSTROUTING -s 10.4.0.1/2 -o eth0 -j MASQUERADE

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Since I also run an Apache2 Webserver on the Ec2 instance, what is the consequence of messing around with iptables as above? Would I still be able to access the webserver?

Many Thanks