I have a RUT955 (FW: RUT9XX_R_00.06.07.7) configured with a L2TP/IPSec-server, DHCP and DynDNS (Noip).L2TP/IPSec, DHCP, DynDNS and WLAN works fine.
In the LAN of the RUT955 there is a GIRA X1 with a fixed IP adress. This is a device which has its own OpenVPN server and ist uses an own dynamic DNS service. The X1 should be reachable from outside with 2 different OpenVPN profiles. The necessary ports forwarding is established.
One VPN profile uses "dev tun". This profile works correct. It returns a IP adress in an internal range of the X1 and it allows access to the X1 only.
The second profile uses "dev tap". This profile does not work. I think it should provide an IP adress from the RUT955 DHCP to the OpenVPN server of the X1 to send it to the remote client. But the client does not receive an IP adress, see attached log.
It is cross-checked with other X1, other clients and access from other site, the result is that it is very likely that the problem is in the RU955, but I have no idea where to search for a misconfiguration!
If necessary I can provide configuration details and the OpenVPN profiles.