IPtables: Forward port to another host is not working

I am trying out something so this is my test setup:

Setup:

I have AWS VPC with a public and private subnet.
I have a host in public subnet with a public IP address (say Host A)
I have a host in private subnet running nginx on port 80 (Say host B with IP address 10.0.1.132 )

What I want to do

I want to access the Webserver on Host B from Internet by visiting Host A.

How

I setup IP forwarding parameter in systctl.conf on host A and then put below iptables rule:

iptables -t nat -A PREROUTING -i eth0 -p tcp --dport 80 -j DNAT --to-destination 10.0.1.132:80

Issue:

It is not working and I am not able to open the WebPage when I visit host A on port 80

Other info (with respect to AWS VPC Security Group):

Here is the kernel info:

# sysctl  -p | grep forward
net.ipv4.ip_forward = 1

Also, I am able to telnet on port 80 from Host A to host B on port 80. So this certifies that my AWS security group is working as expected.

I think I am going wrong on IPtables part. Could help me figure out what is wrong in above setup.

Solution 1:

Do you realize that private host should …