Rancher 1.6 Kubernetes host NAT issues

We are currently setting up a Rancher 1.6 full HA at IBM Cloud (Bluemix/SoftLayer). When we add a host from IBM Cloud it works fine. But we we try to add a Kubernetes host that is in our data center we get timeouts in Rancher. The server is connected through IPSec VPN and the IP is being NATed. We used the NATed address in the docker command.

sudo docker run -e CATTLE_AGENT_IP=“10.XXX.XXX.29” --rm --privileged -v /var/run/docker.sock:/var/run/docker.sock -v /var/lib/rancher:/var/lib/rancher rancher/agent:v1.2.6 http://xxxxxxx.com:8080/v1/scripts/45701EF281E3F583F0C8:1483142400000:2gn1xZPWRJAxZvul1WGPkd8QMY

The machine shows up in Rancher but the Kubernetes processes fail to start. The UDP ports are open between the host.

Not sure what the problem is.