ipfw3 nat to dynamic ip

[samg]

The network looks like this:
WAN ----- [ ISP Router ] ------ [ My Router ] ---- [ My Clients ]
The ISP router is set for IP passthrough, so 1-1 NAT. I don't have a static IP address, the ISP router gets an IP from the ISP via dhcp. So on my router, eth0 is connected to the ISP router, and gets an ip via dhcp, which will be whatever ip the isp router got, and this ip can change from time to time. I'd like to NAT traffic out via eth0, or whatever ip eth0 happens to have at the time.

An aside: does ipfw3 support ipv6 ip's?

Thanks,
Sam

On Fri, Dec 24, 2021, at 5:54 AM, Bill Yuan wrote:
> Hi,
>
> Yes, Currently, it supports IP address only.
> What do you mean by "Dynamic IP address"? 
> Do you mean NAT to iface instead of IP address during the configuration?
> Or can you please help to elaborate?
>
> Regards,
> Bill Yuan
>
> On Fri, 24 Dec 2021 at 07:43, samg <samg at fastmail.com> wrote:
>> Hello,
>> 
>> Is there a way to setup ipfw3 nat to a dynamic ip address? I get an ip from my isp via dhcp. This looks like it used to be possible by nat-ing to an interface, but the current version only accepts ip addresses.
>> 
>> Thanks,
>> Sam