Date: Thu, 23 Oct 2014 21:36:57 +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%2Bwhn7Qb7_aJxWxR8VRXttEqdFRzQFOod45b-cc-mm%2BsMbn=rw@mail.gmail.com> In-Reply-To: <CA%2Bwhn7SZ%2B1dxmcFSU7W5-2%2BJpawvAOVVxMz8VWWWB1mUCi-Ctg@mail.gmail.com> References: <CA%2Bwhn7SZ%2B1dxmcFSU7W5-2%2BJpawvAOVVxMz8VWWWB1mUCi-Ctg@mail.gmail.com>
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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 synproxy > 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.], seq > 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 resul= t > of tcpdump. After some seconds FreeBSD generates RST package both side. > (There is no handshake SYN or ACK packages generated by pf synproxy at th= e > inner interface) > > I think that the problem is about the router beacuse I had had successful > connections before the router device. When I turn off the synproxy or add > "keep state" instead of "synproxy state" I can successfully connecting. > > I want to take your opinions about why the handshake packages could not b= e > generate by pf synproxy? > > Regards, > Tugrul > >
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