The following reply was made to PR kern/33409; it has been noted by GNATS.

From: Darren Reed <darrenr@reed.wattle.id.au>
To: Chapman Flack <nblists@anastigmatix.net>
Cc: gnats-bugs@NetBSD.org, Darren Reed <darrenr@pobox.com>
Subject: Re: kern/33409 ipnat fails with EIO
Date: Tue, 30 May 2006 01:18:22 +1000 (EST)

 > I can repeat the behavior in NetBSD 3.99.20, just as Roland describes:
 > any use of ipnat(8) fails with
 >   ioctl(SIOCGNATS): Input/output error
 > UNLESS 'ipf -E' has been done first.
 > 
 > This seems to be at the very least a doc bug, as our ipnat(8) man page
 > claims explicitly:
 > 
 >   Note that if ipf(8) is not enabled when NAT is configured, it will
 >   be enabled automatically, ...                              ^^ ^^^^
 >   ^^ ^^^^^^^ ^^^^^^^^^^^^^
 
 This is a doc bug and I think it is referring to rc.d scripts doing
 the "ipf -E".
 
 Darren