Synology NAS with OpenVPN with client certificate

For a Synology NAS to setup OpenVPN is not as easy as I thought it would be. Specifically when you enable client site certificate checking it’s not a tick in the box. Below the steps I follow to get it working.

PKI settings

first thing is to setup my own CA so I can create and sign my own server and client certificates. I used an awesome tool for this on github. clone it, then change variables as needed.

git clone
cd easy-rsa/easyrsa3/
cp vars.example vars
vi vars

in the vars I updates for example the following fields;

set_var EASYRSA_DN    "org"
set_var EASYRSA_REQ_PROVINCE "California"
set_var EASYRSA_REQ_CITY     "San Francisco"
set_var EASYRSA_REQ_ORG      "Copyleft Certificate Co"
set_var EASYRSA_REQ_EMAIL    ""
set_var EASYRSA_REQ_OU       "My Organizational Unit"
set_var EASYRSA_CA_EXPIRE    3650

After changing the vars you can create your own PKI CA. Following commands initialize PKI and generate the CA. The CA is important so choose your passphrase wise! If this gets compromised, other certificates can be used to sign client certificates.

./easyrsa init-pki
./easyrsa build-ca

Generate Server Certificate and key

Generate a server certificate and key.

./easyrsa build-server-full synology_NAS_OpenVPN nopass

Two files will be generated, you need these later to upload to your NAS.


Generate Client Certificate and key

Generate a client certificate and key. Or more when you need more devices to connect to the VPN.

./easyrsa build-client-full client_peter nopass

Two files will be generated, you need these later to upload to your device which will connect to the laptop.


Install VPNServer package on Synology NAS

Now you need VPN Server package on your Synology NAS. Go the the admin page, e.g. and go to Package Center > All Packages. Search for VPN Server and click install when found. After installing, don’t run it yet. If already running, click stop. If your remote working on current VPN, please don’t ;)

Now you also need to SSH to you NAS to manual set OpenVPN to listen only to clients with certificate. Otherwise this whole extra certificate (2FA) can just be bypassed.

SSH to you NAS and edit the file below

vi /usr/syno/etc/packages/VPNCenter/openvpn/openvpn.conf

remove the line or comment it with a #


Upload Certificate to Synology NAS

To upload them to you NAS, go the the admin page, e.g. and go to Control Pannel > Security > Certificate. then click Add

  • Add a new certificate
  • Import certificate
    • Private key: use file easy-rsa/easyrsa3/pki/private/synology_NAS_OpenVPN.key
    • Certificate: use file easy-rsa/easyrsa3/pki/issued/synology_NAS_OpenVPN.crt
    • Intermediate certificate: use file easy-rsa/easyrsa3/pki/ca.crt
  • click OK

then again in Control Pannel > Security > Certificate. but now click Configure. select the correct just uploaded certificate behind VPN Server. Now, go back to the package center and click Run for the VPN Server package. If you skip this (restarting VPN Server) you might will talk the VPN Server which is still serving previous certificate.

VPN Server settings on Synology NAS

Now the correct certificate is uploaded and VPN Server is started, you can change some last setting if needed, like;

  • Privilege: Use for a specific VPN user might be a wise Idea, and only give that uses privilegse to OpenVPN
  • OpenVPN: tick Enable OpenVPN server and change setting if wanted.

You now could click Export Configuration but this configuration is incomplete/incorrect. Therefor I generated my own OpenVPN config.

Generate Client OpenVPN config

I used the following configuration for the client. named it VPNConfig-client-peter.ovpn. Be aware this file contains your private key (so this is your 2FA), store it securely or trough it away after setting up the OpenVPN.

dev tun
remote <YOUR PUBLIC IP> 1194
redirect-gateway def1  # if you want all traffic tunneled
proto udp
script-security 2
reneg-sec 0
cipher AES-256-CBC
auth SHA512
remote-cert-tls server
... input from easy-rsa/easyrsa3/pki/ca.crt
... input from easy-rsa/easyrsa3/pki/issued/client_peter.crt
... input from easy-rsa/easyrsa3/pki/private/client_peter.crt

Install OpenVPN Connect

Download and use the above file to connect. and login with user credentials you have given privileges to use OpenVPN (see above)

That should do it. Good luck!

Kill busy session via Raritan CLI

On the GUI it was simple to find to kill a busy session on a console port, but I couldn’t find a way to force logoff a busy session in CLI

when you logged in and you find yourself a busy console and you don’t want to login all the way to the GUI and clear it, this is the CLI command’s for this;

admin > 20
Sorry, port is busy!
admin > maintenance 
admin > Maintenance > logoff port 20
Force log off successful.

admin > Maintenance > top
admin > 20
You are now master for the port.
 Escape Sequence is: Control-]

And it’s all yours again \o/

This was on a Dominion SX2; model DSX-32.

Pi-Hole and PowerDNS

Since a while I’m using Pi-hole in my home to filter all kinds of domain names. This in combination with a PowerDNS resolver makes gives me more privacy. At least not monitored by the ‘free’ DNS resolvers out there…

PowerDNS is running on my Synology NAS in a docker container. Pi-Hole is still running on a Raspberry Pi 3 Model B+ since I wanted to test first and did not want to touch my working PowerDNS setup. but it already running fine for a while and I need to still move form the Pi to a docker as well. I will update this post when I moved everything with the detailed docker information as well.

Currently Pi-Hole v5 is just out, so I want to wait for a short moment when the fist fixed are done and the move to docker as well.

Cool thing with Pi-Hole is that you can use your one blocklists. Some I took form

Related links;