I know why you're here. It's because you want to connect to your local network via WWW, but Synology's guides aren't complete, and a bit out of date, right? I don't know why I'm asking, as you can't respond. Anyhow, let's get to it.

Step 1: Setting up the your Router

Router Config

In your router, you'll need to set up port forwarding or "Virtual Server" or "NAT Settings":

  • UDP port 500 (IKE)
  • UDP port 1701 (L2TP)
  • UDP port 4500 (IPSec NAT-Traversal)

These must be pointed to your Synology's internal IP address, like 192.168.x.x or 10.10.x.x. You also may need to unblock these in your Firewall.

Step 2: Setting up the VPN Server

Synology VPN Config

If you haven't installed the VPN Server package from Synology on your NAS, you'll need to do this.

You have three main options for setting up a VPN, only two of which are real options: OpenVPN and L2TP over IPSec. The path of least resistance is L2TP over IPSec. You'll only need to configure the IP address, which should be in the same host range (the last two octlets). My network is 192.168.50.x. To avoid any IP conflicts, I just add +1, so my VPNed devices will be 192.168.51.x.

The second piece is the Pre-shared key. Assign this to whatever you'd like, but you will need this password.

Step 3: Setting up your Mac

Locate VPN in the system settings; in modern macOS, search "VPN," and it'll appear in the sidebar. Click add VPN configuration, and select L2TP over IPsec.

VPN Config in macOS for Synology

You'll need to configure the following:

  • Display name: This can be anything
  • Server address: This is your network's external IP. I couldn't get the quickconnect URL to work, but there is probably a way. The easiest way to determine your IP is to use a "What's my IP" search in a web browser when connected to the same network as your Synology.
  • Account name: This must be a Synology user on your NAS. You can create an account just for VPN or use an existing account
  • Password: This is your password for the Synology user.
  • Shared Secret: This is the pre-shared key you set up in the Synology VPN server.

To test the connection, you'll need to use an external network; if you have an iPhone, a quick and easy way is to connect your Mac to your iPhone as a hotspot and test the VPN connection.

If you have issues connecting anything on your network, in your VPN configuration, click options and select "Send all traffic over VPN connection". This is a brute force method that'll do exactly what it says. Your Mac essentially exists on the same network as the rest of your devices.