Can't access nginx accessible on private ip but not on public ip

Question

I'm creating resources using terraform and I have a node in the subnet 172.1.0.0 with no security group or rules assigned to the node; the node has two endpoints 22 and 80.

I used nmap to confirm that the ports are open and they are:

nmap -Pn -sT -p T:11 some-ingress.cloudapp.net

Starting Nmap 6.47 ( http://nmap.org ) at 2016-07-08 19:02 EAT
Nmap scan report for some-ingress.cloudapp.net (1.2.3.4
Host is up (0.31s latency).
PORT   STATE SERVICE
22/tcp open  ssh

Nmap done: 1 IP address (1 host up) scanned in 1.34 seconds


nmap -Pn -sT -p T:80 some-ingress.cloudapp.net

Starting Nmap 6.47 ( http://nmap.org ) at 2016-07-08 19:02 EAT
Nmap scan report for some-ingress.cloudapp.net (1.2.3.4)
Host is up (0.036s latency).
PORT   STATE SERVICE
80/tcp open  http

Nmap done: 1 IP address (1 host up) scanned in 0.09 seconds

I've installed nginx on the node and running curl 172.1.0.4 and curl 127.0.0.1 and curl 0.0.0.0 gets me the default nginx page.

However running curl <public ip> or curl <dns name> hangs and I get a

curl: (56) Recv failure: Connection reset by peer

My iptables rules are:

Chain INPUT (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     udp  --  anywhere             anywhere             udp dpt:bootpc
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:domain
ACCEPT     udp  --  anywhere             anywhere             udp dpt:domain
ACCEPT     tcp  --  anywhere             anywhere             tcp dpt:bootps
ACCEPT     udp  --  anywhere             anywhere             udp dpt:bootps

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         
ACCEPT     all  --  anywhere             anywhere            
ACCEPT     all  --  anywhere             anywhere            

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination  

Why can't I possibly access nginx at the node's public ip?

The node is in a virtual network 172.1.0.0/16 and a subnet of 172.1.0.0/24 I can post the terraform configs if needed.

Answer 1

There could be a number of reasons for this:

1. I'm assuming this is deployed in a VPC.

Typically, if you are using a VPC, then you would have to add an Internet Gateway and setup the route tables associated with your subnet with a route which says destination 0.0.0.0/0 send to igw.

Hope this helps.