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I have a network bastion which is publicly accessible at example.compute-1.amazonaws.com and a private postgres database instance at postgres.example.us-east-1.rds.amazonaws.com:5432

I can ssh into the bastion using

$ ssh -i key.pem [email protected]

Then once I'm in the bastion I create a ssh tunnel with:

$ ssh -i key.pem -L 5432:postgres.example.us-east-1.rds.amazonaws.com:5432 [email protected]

I can then verify that the tunnel works by connecting to the database from the bastion using localhost:

$ psql -p 5432 -h localhost -U postgres

However, I am unable to connect to the database remotely (without being in the bastion).

$ psql -p 5432 -h example.compute-1.amazonaws.com -U postgres
psql: could not connect to server: Connection refused
Is the server running on host "example.compute-1.amazonaws.com" () and accepting
TCP/IP connections on port 5432?

I've configured the security group of the bastion to accept inbound traffic on port 5432.

Am I using ssh -L correctly? Should I be using it outside the bastion? Any advice would be much appreciated.

2 Answers 2

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When you create an SSH tunnel, it does not expose the opened port to the outside world. The opened port, is only available as localhost. So effectively what you've done is to create a tunnel from your bastion, to your bastion.

Instead, what you want to do is create a tunnel from your local computer through your bastion.

So, you create your tunnel as part of your connection from your local computer to your bastion. You do not need to create another SSH connection.

So, locally, you would execute:

$ ssh -i key.pem -L 5432:postgres.example.us-east-1.rds.amazonaws.com:5432 [email protected]

Assuming postgres.example.us-east-1.rds.amazonaws.com resolves to the private IP address.

Then to connect to your server, still locally, connect as if the server was local:

$ psql -p 5432 -h localhost -U postgres

Doing this, there's no need to use a prompt on your bastion.

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  • This worked for me, thanks! The one thing I did forget for anyone who's psql command just hangs there: Make sure that your db security group allows access from the bastion.
    – Goran
    Commented Apr 13, 2018 at 5:31
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This worked for me. Make sure you have psql client installed locally.

psql --host=myAwsDbEndpointUrl.ciqykqusf0nv.us-west-1.rds.amazonaws.com --port=5432 --username=myUserName --password --dbname=myDbName

When creating your db instance on aws, make sure to define the following:

  1. username
  2. password
  3. database name
  4. port number

I also had to create a security group for the VPC that the database was located in. After creating it make sure your db instance uses this for its security group. The security group has the following rules:

inbound--> type:PostgreSQL, protocol:TCP port range:5432, source:0.0.0.0/0

outbound--> type:All Traffic, protocol:All, port range:all, destination:0.0.0.0/0
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  • That is not going via a bastion though, right? You are just connecting directly to RDS
    – RhysC
    Commented Jan 27, 2017 at 2:27
  • It goes through a vpc that the rds instance is exposed through. You attach the vpc to the rds instance upon creation.
    – Tim Siwula
    Commented Jan 27, 2017 at 3:36
  • Yeah i think the original question was with regard to going via a bastion server in the VPC so the RDS instance is not publicly exposed (well thats how i read it)
    – RhysC
    Commented Jan 27, 2017 at 5:59
  • That was not the question and your answer doesn't help solving the problem at all. Commented Sep 21, 2018 at 8:08

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