Power BI DirectQuery to AWS RDS PostgreSQL via SSH Tunnel – SSL Certificate Validation Error

KalpeshClearDu 

This is a known and painfully tricky issue when trying to use DirectQuery over an SSH tunnel with SSL-enabled PostgreSQL (especially via AWS RDS). You’ve done almost everything right, and it’s clear this isn’t just a standard connectivity problem — it’s certificate validation inside Power BI’s DirectQuery engine, which behaves differently from Import or tools like pgAdmin.

Option 1: Use Server Compatibility Mode in connection string

Power BI allows advanced parameters — try tweaking the SSL behavior directly:

1. When connecting in Power BI, choose DirectQuery, then select Advanced options.

In Additional settings, add:

Trust Server Certificate=true;
Ssl Mode=Require;

Option 2: Modify the hosts file + use actual RDS endpoint

You can trick Power BI into thinking it's talking to the RDS endpoint:

1. Open your local hosts file (as admin):
   C:\Windows\System32\drivers\etc\hosts

Add a line like:
127.0.0.1 your-rds-endpoint.rds.amazonaws.com
Then connect in Power BI using:
your-rds-endpoint.rds.amazonaws.com

This matches the SSL certificate’s hostname, even though the SSH tunnel is to localhost.

⚠️ Be sure that your tunnel is forwarding to localhost:5432 in this case.

Option 3: Use a Power BI Gateway (for scheduled refresh, not desktop)

If your end goal is Power BI Service (not just Desktop), you'd typically need to:

• Configure the On-premises data gateway to use ODBC + Import (DirectQuery to private RDS is not fully supported out-of-the-box via SSH tunnels)

• Or host a custom service on EC2/VPN that routes securely

But since you're focused on Desktop testing, this doesn’t help you immediately.

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