OpenVPN Connect Client cannot connect to RDS instances

[c0delift]

Hello, I'm not sure if this is the correct place for this question, but it seems relevant. If not please direct me to the correct subforum!

I have been tasked with getting a VPN setup for my company on EC2 using the OpenVPN Access Server AMI in the AWS Marketplace. I was able to go through the setup guide, creates users and clients, have people connect to the VPN via OpenVPN Connect Client and connect to EC2 instances residing the same VPC as the VPN instance.

I however am having trouble with connecting to RDS instances when connected to the VPN via the client. The RDS instances are not publicly accessible, hence why connecting through a VPN is necessary. We had an old, decrepit VPN setup that was not documented and steup by a contractor ~2 years ago which was able to connect to the RDS instances without issue. This is sadly not documented so I could not mimic the configuration setup verbatim.

For some added context, if I ssh into the access server, I am able to connect to the RDS instances via telenet, however when connecting on my local machine via the OpenVPN Connect Client it does not connect. I've done some pretty heavy googling on this and have come across a few posts that looked helpful, though didn't end up solving the issue.

Has anyone else seen something like this? Thanks in advance for any insight!

[novaflash]

I would suggest this page as your first stop:
https://docs.openvpn.net/troubleshootin ... pn-tunnel/

[c0delift]

I ended up figuring out the issue. Looks like a couple DBs were in a different VPC than our others. The other VPC had a different CIDR range of private IPs. I had to grant the clients access to this through the Admin Server console.

[novaflash]

Alright, glad to hear you were able to solve it.