so to access grafana over the vpn try using the ip of the virtual IF. 10.147.17.36:4000

if this doesn't work use this command to NAT the address
sudo iptables -t nat -A PREROUTING -d 10.147.17.36 -p tcp --dport 4000 -j DNAT --to-destination 192.168.178.36

Then connect again to 10.147.17.36:4000 and the firewall will NAT the address to the eth0 interface and it should work

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