natd + ipfw question

[Luigi Rizzo]

On Tue, Dec 23, 2003 at 03:17:12PM -0500, Leo Bicknell wrote:
...
> I must not be clear on what "in" "out" "recv" and "xmit" mean, and
> after reading the manual page 3 times I'm now even more confused.

The names are reasonably intuitive...

  "in"		matches packets on the INput path (basically,
		ip_input() and/or ether_input()

  "out"		matches packets on the OUTput path;
		(ip_output() and/or ether_output())

  "recv foo0"	matches packets that have been received from
		interface "foo0"

  "xmit bar1"	matches packets that are going to be transmitted
		on interface "bar1"

  "via xx2"	matches packets that are either received or
		transmitted through interface xx2

the flow diagram near the beginning of the ipfw manpage should
clarify things a bit (i agree that the wording of 'recv/xmit/via'
section is a bit confusing, so if you have better suggestions they
are welcome)

	cheers
	luigi