Date: Fri, 24 Oct 2014 13:52:53 +0300 From: Tugrul Erdogan <h.tugrul.erdogan@gmail.com> To: freebsd-pf@freebsd.org Subject: Re: SynProxy had a trouble when located front of a router device Message-ID: <CA%2Bwhn7S8FUYz3CRJj_1p%2BOb2EZODH5qT-44OaT6OtLUuFRutWg@mail.gmail.com> In-Reply-To: <CA%2Bwhn7Qb7_aJxWxR8VRXttEqdFRzQFOod45b-cc-mm%2BsMbn=rw@mail.gmail.com> References: <CA%2Bwhn7SZ%2B1dxmcFSU7W5-2%2BJpawvAOVVxMz8VWWWB1mUCi-Ctg@mail.gmail.com> <CA%2Bwhn7Qb7_aJxWxR8VRXttEqdFRzQFOod45b-cc-mm%2BsMbn=rw@mail.gmail.com>
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I have important founding. I think it is about VLAN between FreeBSD-Router 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 routing 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.com= > wrote: > Update: > > The topololgy has been redrawed below: > > > | Atacker | <-> | FreeBSD | <-> | Router | <-> | Victim | > > > Thanks, > > > PS: Although connections lost by pf synproxy, the pings (form attacker to > 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 have= 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. Without >> synproxy rule I have successfully conneting. Whenever I activate synprox= y >> 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], seq >> 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.], se= q >> 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 [.], ack >> 1, win 5840, length 0 >> 21:09:56.533680 IP AA.BB.183.93.51510 > AA.BB.189.100.80: Flags [.], ack >> 1, win 5840, length 0 >> 21:10:02.532255 IP AA.BB.183.93.51510 > AA.BB.189.100.80: Flags [.], ack >> 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 both >> side. (There is no handshake SYN or ACK packages generated by pf synprox= y >> at the inner interface) >> >> I think that the problem is about the router beacuse I had had successfu= l >> connections before the router device. When I turn off the synproxy or ad= d >> "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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