Where can I find information on ipfw nat global?

Question

Computer networks

Good afternoon.
I'm trying to set up a gateway with channel balancing from two providers.
I came across an article: birdofluck.livejournal.com/8778.html which briefly mentions ipfw nat global. I can't find more info on how to set it up.
Can someone tell me in more detail how it works, or at least poke their nose where to read ?! :)
I'm also looking for suggestions for other modern balancing options on FreeBSD

Answer 1

There are built-in balancers in iptable and pf. But they are, so to speak, high-level.
Using ipfw, you can make the system extremely flexible.
I did balancing and redundancy using ipfw. For several years now, the flight has been normal.
The best reference for ipfw is man ipfw without it anyway.
In balancing, the main thing is not nat global, but several routing tables.
Switching between tables is carried out in the general case using ipfw prob.
At one time it helped me a lot that procedures appeared in ipfw:
ipfw call and ipfw return I
actively use them.
I also made my config based on the "improved firewall": www.opennet.ru/base/net/advanced_ipfw.txt.html
Such a config is more structured and easier to read, although some introductory is needed.
In general, no matter how much I searched for a normal howoto on building a balancer based on ipfw, I did not find it. Everywhere there were only ideas and thoughts. So I had to think a lot myself, but I'm happy with the result. He himself never gave birth to an article, although it could have been.
If you need help, there is soap in the profile. I'm on vacation right now, so I can't guarantee the speed :)