You can change RouterOS symmetric nat, to full cone nat?

RouterOS General
1

You could make a rb with symmetric nat, work as a router with nat: full cone nat?

2

Edit my post, I think now is more clear my query.

3

you can do 1:1 NAT, but it works statically, not in dynamic manner. also, UPnP is an option

4

How good solution is UPnP? What other options do I have for the nat symetrico certain calls is not ruining my provider works with STUN server, I have dynamic ips and ports RTP are many variables over time, I mean the port forwarding is not as effective.

Some speak of a DMZ, other tunnels, Layer 7.

That would be best for the nat simmetrico not miscarry calls, 100 calls, 10 go wrong.