How to configure natd to work with multiple interfaces?

Question

FreeBSD

Good afternoon.
There is a server with FreeBSD and three network interfaces:
em0 - interface to the Internet (address 10.0.2.15);
em1 - interface to the first local network, there is a machine 192.168.1.10 with an FTP server;
em2 - interface to the second local network (address 192.168.0.1)
The problem is to make natd work with 2 interfaces (em0 and em2), so that when accessing 10.0.2.15 or 192.168.0.1 via 21 via FTP, a redirect is made to 192.168.
As an option, you can run two natds, but I would like to try something more elegant. Found that natd has such a thing as instance. I tried these configs:
natd:
instance default
interface em0
port 8668
redirect_port tcp 192.168.1.10:20-21 20-21
instance local
interface em2
port 8888
redirect_port tcp 192.168.1.10:20-21 20-21
globalport 8000
When starting natd with this configuration, it returns null, although it hangs in natd processes. What is it connected with?
+ how to set up a firewall in this case?

Answer 1

natd is no longer relevant. Use nuclear nat. There you can raise several instances with different settings. man ipfw for examples of using NAT.

Answer 2

I know that natd is out of date, but it just became interesting how to use instances in natd. But thanks, I'll try in nuclear nat.