VPN Server - connect via PC and connect via iOS device

[lemonadepop]

[SOLVED - I leave here the issue for others in case it helps]

DSM 6.2 on RS815+

I have successfully set up VPN Server (in UK) on DSM 6.2 and can connect my PC (in France, LAN wifi) via Windows 10 inbuilt VPN client using L2TP/IPSec.

However, I cannot get the VPN working on an iOS device. I get the message "VPN Connection: The L2TP-VPN server did not respond. Try reconnecting If the problem continues, verify your settings and contact your Administrator". I have tried on LAN wifi, and on mobile data 4G. Same error.

I tried setting up a second user on the VPN server. Again, could connect via Windows 10, but not via iOS. Spent hours trying to troubleshoot, but am stuck in a google-search and youtube loop where I am getting no further.

Any ideas?

 

[lemonadepop]

[SOLUTION]

Port forwarding!

Turns out that my Windows 10 VPN client was happy with the port forwarding rules on the receiving network with ports 1194 UDP, 1701 UDP. It was enough.

However, iOS VPN client required ports 500 UDP and 4500 UDP to be added. Once added to firewall, it worked!

 

[mathematics28]

[SOLUTION]

Port forwarding!

Turns out that my Windows 10 VPN client was happy with the port forwarding rules on the receiving network with ports 1194 UDP, 1701 UDP. It was enough.

However, iOS VPN client required ports 500 UDP and 4500 UDP to be added. Once added to firewall, it worked!

I know its resolved, but did you consider Tailscale to simplify this?