VPN Server - clients can't reach Synology via its original IP?

VPN
1

I have L2TP VPN server running on my Synology (192.168.1.3), with VPN IP range being 10.2.0.0 (the final 0 is a fixed value on the GUI and cannot be changed).

Whenever a client is connected to the VPN, it can reach all other devices in LAN except the NAS itself, e.g. ping to 192.168.1.3 unsuccessful. Instead I discovered the address for Synology becomes 10.2.0.0 for the VPN clients.

Not a huge issue but definitely a bit of a nuisance. I have to change the IP address to access services like DS Cam etc depending on my location.

Any way around that ? (other than setting up a docker VPN Server… Although I am considering going there if there is an IKEv2/IPSec server available, since Android 12 no longer supports L2TP connections)

Thanks for any help.

2

Set up a static route on your router. So the network destination is your VPN subnet, in my case, 10.8.0.0 then the subnet mask of your LAN and then the gateway is your NAS IP. I had to do this to solve the exact same problem as you and it worked for me.

3

Check out https://tailscale.com/ free tier. It might make your life simpler.

4

OpenVPN lets you use the original IP

5

I have that configured already… if this is what you are talking about:

https://imgur.com/a/DRRVMA1

What this did to me is that my on-premise LAN clients can now see and access / ping my VPN clients with this config. But for me I still cannot have my VPN clients go “connect to 192.168.1.3” and they reach my Synology.

VPN clients still need to enter “connect to 10.2.0.0” to reach Synology…

6

I know just a little about tailscale and zerotier. Haven’t tried any of them. But my assumption is that each of the devices will have to have some client installed.

Although just a one-off process (and then it is always on right?) If VPN serves my needs I will just keep things as is… But thanks for the suggestion.

7

It doesn’t let you use the original IP

8

I’m assuming 192.168.1.3 is your NAS IP? Another thing to check is in the advanced network settings on your NAS uncheck use multiple gateways if it’s enabled.

9

Also, have you considered using OVPN rather than L2TP?

10

This is probably it then. I need to have multiple gateways checked for some other services that I open to outside. Guess I will have to live with using 10.2.0.0 in that case.

11

For some reason I want to stick with native VPN protocols on my phones and Windows laptops. OpenVPN needs client installation… So not considering it for now.

12

Yeah the multiple gateways option broke the routing for me. When unchecked I can access the NAS whilst connected via VPN. However, if you need it on…