Date: Wed, 04 Feb 2015 13:13:04 +0800 From: Julian Elischer <julian@freebsd.org> To: freebsd-ipfw@freebsd.org Subject: Re: [RFC][patch] Two new actions: state-allow and state-deny Message-ID: <54D1AA60.4030907@freebsd.org> In-Reply-To: <54D0A1AA.4080402@FreeBSD.org> References: <54CFCD45.9070304@FreeBSD.org> <20150203205715.A38620@sola.nimnet.asn.au> <54D0A1AA.4080402@FreeBSD.org>
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On 2/3/15 6:23 PM, Lev Serebryakov wrote:
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> On 03.02.2015 13:04, Ian Smith wrote:
>
>>> Now to make stateful firewall with NAT you need to make some not
>>> very "readable" tricks to record state ("allow") of outbound
>>> connection before NAT, but pass packet to NAT after that. I know
>>> two:
>>>
>>> (a) skipto-nat-allow pattern from many HOWOTOs
>> Lev, can you provide references for these HOWTOs you refer to?
>>
>> I have a suspicion that some of them should be taken out and shot.
> google for "FreeBSD ipfw nat stateful" :) There are lot of them. Not
> real HOWTOs, but blog posts & alike.
>
> BTW, without new mechanism it is really hard to do such firewall, as
> we need action (nat) after "allow keep-state". It could be done with
> this ugly skip-to or with "allow keep-state" in INCOMING section of
> firewall, what is not much better, as I prefer to decide let packet
> out or not in OUTCOMING part of firewall and with "allow keep-state"
> in incoming path it flood state table with unused states.
>
> Another problem, that "keep-state" acts as "check-state" too, so you
> could not have ANOTHER "keep-state" before NAT in outgoing part or you
> miss nat completely (sate is created in outgoing path, and then
> checked before nat in outgoing path with "keep-state", grrrrr, ugly!).
yes I think "keep-state" should be deprecated and replaced or
supplemented by 'save_state' that does NOT do an implicit
'check-state'.. I don't know whose idea that was but it's just wrong.
(if the state exists, maybe just replace it..)
>
>
> - --
> // Lev Serebryakov AKA Black Lion
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