So what I want to do is the following:
I want to be able to access a RB951 router within an internal network, by adding port forwarding settings on a RBLHG5 that’s connected to the RB951.
I know I need to enable specific dst-nat settings on the firewall, but I’m not completely sure which settings to enable.
There is nothing special about the second router. Think of it as as just a server for example ( an IP address on the LAN is an Ip address on the LAN)
So on the first router there is nothing new.
You need to have a dst-nat rule for each forwarding
You need a firewall rule to allow that dst-nat traffic to reach the server (router).