Cannot run EC2 instance - got REFUSE_CONNECTION

Question

I'm studying AWS. 
I'm creating VPC, Subnet (us-east-1a/1b for public and 1a/1b for private with different Ipv4).
I created Route Table for private/public route for private/public subnet. Private will explicit 2 subnet private and public is without explicit 2 subnet.
Internetgateway is attached to VPC.
Using Internetgateway to public Route table
Create NAT gateway and attached to private Route table
Create security group: attached VPC, inbound I set all traffic

After that: I use command like this to create EC2
aws ec2 run-instances --image-id  --instance-type  --security-group-ids  --subnet-id  --key-name  --user-data

My EC2 is running. However, when I click on the "Public IPv4 address". I will open a new window and I got the REFESUE CONNECTION from that.

I don't know what I miss configuration. 
The expected value that the website will show something like this is the instance is in the subnet with ID:...

Answer

Hi David

Website on which EC2?
Public - check security groups- that allow http traffic.
Private thru Public - may require little magic with reverseproxy on Public one

Thanks,

Answer

Hi David,

So one by one:
Check that http service is up, in LISTEN mode on EC2 level:

```
ss -l | grep -e http 
```
you can check it also using on EC2 level:
```
curl http://127.0.0.1
```
and see that this connect.

If doesn't run, you need to start http server.

Then check that SecurityGroup is really connected to the specific EC2.
Ensure that you have not blocked traffic by NACL by mistake on VPC level.

Thanks

Answer

Hi,

I hope that I understand your issue correctly.

Theory:
The public network should be used as public one, so should have InternetGateway.
The private network should be used as private one, so should not have InternetGateway.

Now, if you setup like above, once you will put machine into public network and assign public IP you should be able to connect, of couse if you have proper SecurityGroup in-place.
If you put machine into private network, even if you assign public IP it won't be accessible due missing InternetGateway in that network.
NAT gateway is only for outgoing connection, should be placed into public network and then allow machines from private network to reach internet (if proper routing is done).
Anyway NAT Gateway is for outgoing connection only, you won't reach any machine from outside using NAT Gateway.

[https://docs.aws.amazon.com/vpc/latest/userguide/vpc-nat-gateway.html]()

Thanks,

Answer

Ensure your security groups allow correct ports or http and https to your ec2.

Cannot run EC2 instance - got REFUSE_CONNECTION

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