我试图通过公共ec2实例连接私有ec2实例时如何解决错误？

Question

I'm creating 2 amazon elastic cloud compute instances one is public and one is pvt.
How can I access the private instance through public instance?
What are the commands to execute? I've tried with

ssh -p port number public-host name private-host name

I got the error as access denied

Answer 1

It appears that your situation is:

• An Amazon EC2 instance in a Public Subnet (connected to an Internet Gateway)
• An Amazon EC2 instance in a Private Subnet (not connected to an Internet Gateway)
• You can successfully SSH into the Public instance
• You then wish to SSH into the Private instance

You will need to use the standard SSH command:

ssh -i pemfile.pem ec2-user@PRIVATE-IP-ADDRESS

Some things to note:

• Connect to the Private instance via its Private IP address. In fact, it should not have a public DNS name or public IP address
• You will need to provide an key (pem) file to authenticate

There are two ways to provide the pem file:

• Use Agent Forwarding in your SSH connection, or
• Copy the pem file to the Public instance and use it as part of the ssh command (as shown above). This is bad from a security perspective since somebody who gets into the Public instance would then be able to access the Private instance.

Also, it depends on whether you are using the same key or a different key on the private computer. The easiest is to use the same key, which makes Agent Forwarding easier.

See: Securely Connect to Linux Instances Running in a Private Amazon VPC | AWS Security Blog