On 7/30/15 3:34 AM, Julian Elischer wrote:
On 7/29/15 10:23 PM, bycn82 wrote:
/Hi,/
/But I dont understand why you said C->D is already in the dynamic
table? which line create the dynamic rule for it?/
/it happened on a previous packet at some other rule, for example
30 allow ip from any to D 80 keep-state
reread the original example description..
/
/
/
/Regards,/
/bycn82/
On 29 July 2015 at 22:03, Julian Elischer <[email protected]
<mailto:[email protected]>> wrote:
On 7/29/15 5:26 PM, bycn82 wrote:
/Hi Julian,/
/
/
/So below are the rules in your example/
/
/
/5 skipto 10 from A to B
/
/6 skipto 11 from any to any/
/10{action} from A to B keep-state/
/11{action} from C to D/
/
/
/
/
/If I remove the "skipto" rules they will become/
//
/10 {action} from A to B keep-state/
/11 {action} from C to D /
/
/
/Correct me if I was wrong, but in my opinion, the rule 5 and
10 are almost the same, so I dont see the benefit by
introducing the "skipto" rulees. //IMHO, the "check-state" is
to speed-up some selected packets, it will slow-down all other
unexpected packets at the same time./
/
/
/so because C -D is already in the dynamic table it triggers on
10 and never reaches 11.
see? you fell for it too.
/
/Regards,/
/bycn82/
On 29 July 2015 at 15:39, Julian Elischer <[email protected]
<mailto:[email protected]>> wrote:
On 7/29/15 3:43 AM, Lev Serebryakov wrote:
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On 28.07.2015 08:30, Ian Smith wrote:
I have global lack of any spare time (and all my
FreeBSD activity is
only a hobby) for last ~2 months. I see the end of this
unfortunate
state of affairs in near future and I remember about
these examples.
there are some simple examples of things this patch
addresses..
For example in the current code, the following (extemely
simplified) set of
rules will not do what you would think when you are working
with a tcp
session from A to B and another from C to D *which has
previously been accepted with a keep-state at some other
point in the
ruleset*
10 {any action} from A to B keep-state
20 {any action} tcp from C to D
because despite the fact that you are only triggering on a
'setup' packet for A to B, any rule
that includes "keep-state" does a "check-state" implicitly.
so the packet from C to D never gets past rule 10.
the only way you can do this is to prefix rule 10 by
something like
5 skipto 10 from A to B
6 skipto 11 from any to any
to make sure packets that are not A to B do not hit the
hidden 'check-state' .
this is a very simple example and yes there are ways to
get around it,
but it complicates the ruleset and increases errors
that reminds me I'd also like to be able to put a "not" at
the
front of the rule matching to negate the whole test but it
doesn't seem to like that.
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