Setting up VPN on your Synology DiskStation is usually pretty easy. But in the last few years IPv4 is being phased out so more and more internet providers don’t assign public IPv4 addresses to their customers. Usually all the new contacts are set up with an IPv4 / IPv6 DualStack. This enables IPv6 contracts to still access IPv4 resources on the net.

The problem: These contracts don’t have a public IPv4 address, so setting up a remote connection to the network is tedious. The good thing: The contracts still have a public IPv6 address.

Setting up VPN on your DiskStation

1. Install the necessary packages to your DiskStation

Install Synology VPN Server

  1. Open the Package Center
  2. Search for VPN
  3. Install VPN Server
Synology VPN Server in the Package Center
Synology VPN Server in the Package Center

2. Configure the DiskStation’s Network Settings

Set up DDNS

  1. Open Control Panel
  2. Go to External Access
  3. Open DDNS tab

    Synology DDNS settings
  4. Click Add
  5. Select Synology. This will provide you with a synology.me address which always points to the current IP address of your DiskStation. We need this address to forward to from the IPv4 to IPv6 Mapper.

    Synology.me settings
  6. Click OK

Configure the LAN’s IPv6 settings

  1. Open Control Panel
  2. Go to Network
  3. Open Network Interface Tab
  4. Click Edit
  5. Go to IPv6 Tab and set your IPv6 setup to DHCPv6-PD. This will set your DiskStation’s IPv6 prefix. You need this to set up the Synology VPN Server. This step is important, as the VPN wizard will only work after enabling this option.

    IPv6 setting of your default network interface
  6. Click OK

3. Configure Synology VPN Server & Enable OpenVPN

With a port forwarding service only OpenVPN can be used, as it is the only protocol supporting TCP.

Enable OpenVPN

  1. Open VPN Server
  2. Go to OpenVPN tab
  3. Select Enable OpenVPN Server
  4. Set Protocol to TCP
  5. Set Enable IPv6 Server mode to true
  6. If you want, you can make your entire network accessible using VPN by checking the allowing clients to access server’s LAN box.
  7. Select the IPv6 prefix you previously set up.
  8. Click Apply
OpenVPN settings

Your OpenVPN Server should now be running. Select Export configuration to export your VPN settings to import into an OpenVPN client.

Setting up port forwarding

4. Set up port forwarding on the router

This step will highly depend on your router. Open it’s configuration page and go to the port forwarding settings. the port should be your VPN port, in this case it would be 1194. The router and forwarding port should be the same. The IP address is your Synology’s public IPv6 address. You can find it under Control Panel -> External Access and then External address. The IPv6 address is the one with the one looking like 1234:d432:7493:123:32ff:dddd:1456.

Setting up an IPv4 to IPv6 Mapper

5. Set up a IPv4 to IPv6 Mapper with feste-ip.net

  1. Go to feste-ip.net
  2. Register for an account.
  3. Go to https://www.feste-ip.net/account/mapsys/list/ and select create.
  4. Select an alias, this will be the URL you will use in your VPN
  5. Put the OpenVPN port into the forwarder. In this case it is 1194
  6. Save the form

The VPN should be accessible now. You can now use a OpenVPN client to connect to it.

Using an OpenVPN client to connect to your network

6. Setting up OpenVPN

  1. Download the OpenVPN client here.
  2. Install the client,
  3. Launch the client.
  4. Just unzip the VPN configuration you downloaded from your DiskStation and edit the VPNConfig.ovpn file. The only change you need to do is replace the line „remote YOUR_SERVER_IP 1194“ with „remote THE_SERVER_IP_OF_YOUR_PORTMAPPER YOUR_PORTMAPPERS_PORT„. You can find the information here:
  5. Import the VPN settings.
  6. Connect to your VPN server.

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