ipfw/nated stateful rules example
xfb52 at dial.pipex.com
Tue Jan 20 07:26:27 PST 2004
> The conclusion so far is that ipfw1 and ipfw2 using keep-state rules
> on the interface facing the public internet with divert/nated does
> not work period.
Probably my post hasn't reached you yet. I think you are mistaken if you mean
that keep-state rules cannot be securely used in a NAT configuration -- see
two examples in my post. The mistake I believe you are making is in talking
about only the public-internet facing interface. What you are trying to do is
to ensure that *conversations* from anywhere on your internal network can be
keep-stated when talking to the external network. But the packets *start* on
the internal facing interface. It just so happens that without NAT you can
ignore this bit of the conversation, but once you include it, you cannot.
In any case, my somewhat messy example which puts the keep-state on a skipto
rule still manages without *looking* at the internal interface, though it does
take into consideration the whole conversation.
> Still would like to be proved wrong on my conclusion.
If you find any bugs in the two alternatives I posted then I would love to know.
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