> Date: Mon, 19 Feb 96 9:12:48 EET
> From: Sakari Aaltonen <email@example.com>
> To: firstname.lastname@example.org
> Subject: ipfw
> Kernels since 1.3.61 will not allow me to MASQUERADE, because ipfw fails with
> ipfw: setsockopt(IP_FW_ADD_FWD): Invalid argument
> There was a note about this on c.o.la. as being a problem with 1.3.61-62.
> It seems to apply to later patch levels, too.
> I have no idea whether or how this can be fixed; it's just that I'm more or
> less dependent on masquerading...
> Sakari Aaltonen
For a while now people have written exactly about this. The solution is
to get ipfwadm-2.0beta2.tgz from ftp.xol.nl. There is also a patch
against kernel 1.3.66 that you must apply due to a bug in the kernel
code. The patch can also be found there.