As of today, I am on a nice and fast new cable modem connection. Unfortunately, that connection is natted to an external shared IPV4 by my ISP. It is only possible to reach my modem via a unique IPV6 address.

Due to this, it is currently not possible to access a NAS that is attached to the cable modem from external via IPV4.

So I came up with the idea to use a spare IP on an external debian wheezy box and setup a VPN server.

Is this a feasible idea, to connect to that server from my synology NAS (it offers the possibility to connect to a VPN Server)? And would the NAS then be available from that spare IP on the debian box?

Any hints are appreciated! thx

migrated from serverfault.com Aug 11 '15 at 22:25

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  • Does the NAS support IPv6? Which transport layer protocol would you use for the VPN? Which application layer protocol would you use to connect to the NAS? – kasperd Aug 11 '15 at 22:27
  • Does the NAS support IPv6? Yes. But it might not be available from the outside unless the modem's (TC7200) firewall is fully disabled. Which transport layer protocol would you use for the VPN? No preference, but secure. Which application layer protocol would you use to connect to the NAS? I'd like to use its http services e.g. connect to admin gui, browse files/photos in its native media viewer (http). Also I'd like to ssh into the box. Ideal would be that I could setup subdomains on my debian box which route ipv4 traffic to the NAS (or any other IPV4 dev @home). – Jabb Aug 12 '15 at 5:55
  • Is the external device mobile? Can it also install OpenVPN? And/Or Can you also use/enable https for your NAS? The external Wheezy box supports IPV4 and IPV6? Your Provider enables you to use a V6-to-V4 gateway outgoing? I'll update my answer accordingly. – Alex Stragies Aug 12 '15 at 14:56

Yes, you can setup this scenario.

  • I assume, your NAS is setup in such a way, that it can access IPV4 and V6 hosts on the internet
  • Install OpenVPN on the Wheezy box. Lets say the free is IP
  • Bind the vpn-daemon to
  • Setup any kind of VPN-client-connection supported by the NAS (tun or tap)
  • UDP will offer better performance, but TCP may be more stable for you.
  • Configure the Wheezy box accordingly
  • Forward (e.g. SSH from to nas-vpn-ip:22), and mount sshfs on your mobile/remote device.

if you use TAP devices, and the NAS can be setup for bridging with the vpn device, you can even vpn-connect your mobile device to the Layer2 of your NAS home network, enabling you to access other devices on your network, if so desired.

I can be more specific, if you need, but in that case, I share kasperd's interest

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