CODEWITHSUNDEEP
amazon-web-servicesamazon-ec2amazon-vpcaws-security-group
user6826691
user6826691

Reputation: 2021

EC2 instance cannot access Internet

I have created a new EC2 instance using terraform for installing vertica, but not able to access Internet or ping google.com within the instance.

I have set up an ec2 instance with a private subnet and have set up nat gateway with a public subnet.

The main route table allows 0.0.0.0/0 as destination and target as the nat gateway.The other route table has the subnet association as the private subnet 10.103.2.0/24. The internet gateway is also attached to the vpc.

My security group for the ec2 instance allows traffic for Redshift and ssh for the following destinations: 10.83.0.0/16,10.100.0.0/16 and outbound all traffic: 10.83.0.0/16,10.100.0.0/16

My Questions:

  1. Should any route table have internet gateway as the target?
  2. Should the security group also allow icmp?
  3. Please brief me how I should troubleshoot and what I should check?

Upvotes: 5

Views: 7079

Answers (3)

tuxlin
tuxlin

Reputation: 1

Based on your responses to the other answers, disabling source/destination check should resolve your issue.

https://docs.aws.amazon.com/vpc/latest/userguide/VPC_NAT_Instance.html#EIP_Disable_SrcDestCheck

Upvotes: -2

Sergey Kovalev
Sergey Kovalev

Reputation: 9411

This statement

The ec2 instance has private subnet

contradicts this statement

I have the internet gateway set up for the route table too

If you have a subnet that has has a route to the internet gateway, you have a public subnet. Your instance will have internet access if all of this requirements are fulfilled:

  1. The EC2 instance has a public IP address.
  2. Network ACL allows inbound and outbound traffic on required ports. Network ACL is like a stateless firewall. It's not enough to allow only outgoing connections.
  3. Your security group should allow outgoing traffic on required ports.

If your instance doesn't have a public IP address, you will need to deploy NAT gateway.

Upvotes: 2

jdevelop
jdevelop

Reputation: 12296

Most likely you haven't defined any internet gateways for your VPC

Upvotes: 1

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