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Date:      Wed, 29 Oct 2014 14:04:17 +0200
From:      Oguz Yilmaz <oguzyilmazlist@gmail.com>
To:        freebsd-pf@freebsd.org
Subject:   Re: SynProxy had a trouble when located front of a router device
Message-ID:  <CAAo%2BKFkpSJwYkUOUbtz%2BcGsKwQmv9O3Bw=VC7Pd7unW%2Bag3cjw@mail.gmail.com>
In-Reply-To: <CA%2Bwhn7S8FUYz3CRJj_1p%2BOb2EZODH5qT-44OaT6OtLUuFRutWg@mail.gmail.com>
References:  <CA%2Bwhn7SZ%2B1dxmcFSU7W5-2%2BJpawvAOVVxMz8VWWWB1mUCi-Ctg@mail.gmail.com> <CA%2Bwhn7Qb7_aJxWxR8VRXttEqdFRzQFOod45b-cc-mm%2BsMbn=rw@mail.gmail.com> <CA%2Bwhn7S8FUYz3CRJj_1p%2BOb2EZODH5qT-44OaT6OtLUuFRutWg@mail.gmail.com>

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Hello,

Does pf synproxy support synproxying when internal side is 8021q VLAN?

Best Regards,

--
Oguz YILMAZ


On Fri, Oct 24, 2014 at 1:52 PM, Tugrul Erdogan
<h.tugrul.erdogan@gmail.com> wrote:
> I have important founding. I think it is about VLAN between FreeBSD-Route=
r
> in diagram.
>
> While Attacker-FreeBSD connection is normal IP connection, FreeBSD-Router
> connection was tagged VLAN 159.
> While FreeBSD-Router connection is VLAN based, synproxy rule State
> Creations value increase, synproxy sends ACKS to the Attacker.
> However synproxy replay with original server does not working ( The routi=
ng
> rule counter on os routing table which redirect packets to FreeBSD-Router
> side is increasing but the packet can not be created  ).
> When I change FreeBSD-Router connection to normal IP connection without
> VLAN, it starts to working.
>
> What can be the problem and solution?
>
>
>
>
> On Thu, Oct 23, 2014 at 9:36 PM, Tugrul Erdogan <h.tugrul.erdogan@gmail.c=
om>
> wrote:
>
>> Update:
>>
>> The topololgy has been redrawed below:
>>
>>
>> | Atacker | <-> | FreeBSD | <-> | Router | <-> | Victim |
>>
>>
>> Thanks,
>>
>>
>> PS: Although connections lost by pf synproxy, the pings (form attacker t=
o
>> victim) can succesfully returns.
>>
>>
>>
>>
>> On Thu, Oct 23, 2014 at 9:25 PM, Tugrul Erdogan <
>> h.tugrul.erdogan@gmail.com> wrote:
>>
>>> Hi,
>>>
>>> I have a trouble at pf synproxy state handshak=C4=B1ng mechanism. I hav=
e been
>>> using pf for years, but first time I have  a router at the backpane of
>>> topology. The schema of my topology given below:
>>>
>>> ---------------------                        --------------------------=
-
>>>                    -------------------         ----------------------
>>>
>>> Attacker                <---------->       FreeBSD(Test)
>>>  <----------->    Router          <---->    Victim
>>>
>>> -------------------                          --------------------------=
-
>>>                      -----------------             -------------------
>>>
>>> I am trying to connect from attacker to the victim from port 80. Withou=
t
>>> synproxy rule I have successfully conneting. Whenever I activate synpro=
xy
>>> state, the client(attacker) side handshaking completing (the outer
>>> interface of FreeBSD device)
>>>
>>> 21:09:53.531421 IP AA.BB.183.93.51510 > AA.BB.189.100.80: Flags [S], se=
q
>>> 1458776780, win 5840, options [mss 1460,sackOK,TS val 1336836512 ecr
>>> 0,nop,wscale 7], length 0
>>> 21:09:53.531494 IP AA.BB.189.100.80 > AA.BB.183.93.51510: Flags [S.], s=
eq
>>> 2093170245, ack 1458776781, win 0, options [mss 1460], length 0
>>> 21:09:53.531524 IP AA.BB.183.93.51510 > AA.BB.189.100.80: Flags [.], ac=
k
>>> 1, win 5840, length 0
>>> 21:09:56.533680 IP AA.BB.183.93.51510 > AA.BB.189.100.80: Flags [.], ac=
k
>>> 1, win 5840, length 0
>>> 21:10:02.532255 IP AA.BB.183.93.51510 > AA.BB.189.100.80: Flags [.], ac=
k
>>> 1, win 5840, length 0
>>>
>>> after that the  "pfct -vvss" showing:
>>>
>>> ix1 tcp AA.BB..183.93:51513 -> AA.BB..189.100:80       PROXY:DST
>>>
>>> and there is no package at inner interface of FreeBSD device at the
>>> result of tcpdump. After some seconds FreeBSD generates RST package bot=
h
>>> side. (There is no handshake SYN or ACK packages generated by pf synpro=
xy
>>> at the inner interface)
>>>
>>> I think that the problem is about the router beacuse I had had successf=
ul
>>> connections before the router device. When I turn off the synproxy or a=
dd
>>> "keep state" instead of "synproxy state" I can successfully connecting.
>>>
>>> I want to take your opinions about why the handshake packages could not
>>> be generate by pf synproxy?
>>>
>>> Regards,
>>> Tugrul
>>>
>>>
>>
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