From owner-freebsd-net@FreeBSD.ORG Thu Mar 15 20:17:59 2012 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 2F2E3106564A for ; Thu, 15 Mar 2012 20:17:59 +0000 (UTC) (envelope-from seyit.ozgur@istanbul.net) Received: from spamtrap.istanbul.net (spamtrap.istanbul.net [85.111.12.34]) by mx1.freebsd.org (Postfix) with ESMTP id BDC058FC1B for ; Thu, 15 Mar 2012 20:17:58 +0000 (UTC) X-ASG-Debug-ID: 1331842673-0426ae630218f520001-QdxwpM Received: from GAMMA.magnetdigital.local (gamma.magnetdigital.local [192.168.131.244]) by spamtrap.istanbul.net with ESMTP id AVqPtLiWFe0r4JaR; Thu, 15 Mar 2012 22:17:53 +0200 (EET) X-Barracuda-Envelope-From: seyit.ozgur@istanbul.net X-Barracuda-RBL-Trusted-Forwarder: 192.168.131.244 Received: from YUHANNA.magnetdigital.local ([fe80::1058:3088:f9b1:1346]) by GAMMA.magnetdigital.local ([fe80::3cca:d6ef:febb:fafb%17]) with mapi id 14.01.0218.012; Thu, 15 Mar 2012 22:17:04 +0200 From: =?iso-8859-1?Q?Seyit_=D6zg=FCr?= X-Barracuda-Apparent-Source-IP: fe80::1058:3088:f9b1:1346 To: Chuck Swiger Thread-Topic: Malformed syn packet cause %100 cpu and interrupts FreeBSD 9.0 release X-ASG-Orig-Subj: RE: Malformed syn packet cause %100 cpu and interrupts FreeBSD 9.0 release Thread-Index: Ac0C5Fxpv2wbk7REQXGSXBWgiq7+JP//5aEAgAAhhBQ= Date: Thu, 15 Mar 2012 20:17:03 +0000 Message-ID: <3807CE6F3BF4B04EB897F4EBF2D258CE5C05F28C@yuhanna.magnetdigital.local> References: <3807CE6F3BF4B04EB897F4EBF2D258CE5C05F221@yuhanna.magnetdigital.local>, <38FA7BAB-AC2B-4515-85CF-27F77C3F4313@mac.com> In-Reply-To: <38FA7BAB-AC2B-4515-85CF-27F77C3F4313@mac.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [172.28.11.161] Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-Barracuda-Connect: gamma.magnetdigital.local[192.168.131.244] X-Barracuda-Start-Time: 1331842673 X-Barracuda-URL: http://10.10.140.221:8000/cgi-mod/mark.cgi X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using per-user scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=9.0 tests=NORMAL_HTTP_TO_IP X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.2.91308 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- 0.00 NORMAL_HTTP_TO_IP URI: Uses a dotted-decimal IP address in URL Cc: "freebsd-net@freebsd.org" Subject: RE: Malformed syn packet cause %100 cpu and interrupts FreeBSD 9.0 release X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 15 Mar 2012 20:17:59 -0000 Thanks for quick reply.. but i don't use firewall. i tried to use PF.. =0A= Packer filter stucks up to 100.000 syn packets flooding(on open port).. Wit= hout packet filter it handle much more syn flooding. Like 1Mpps can handle = w/o interrupts that i see on my equiment=0A= But in this case "malformed packets" i got interrupts also input packet err= or.. cause %100 cpu..=0A= Is there any way to stop them without firewall ? Any rfc kernel feature can= check and stop those bogus packets ?=0A= Or do i something wrong on PF ? =0A= ________________________________________=0A= From: Chuck Swiger [cswiger@mac.com]=0A= Sent: Thursday, March 15, 2012 10:12 PM=0A= To: Seyit =D6zg=FCr=0A= Cc: freebsd-net@freebsd.org=0A= Subject: Re: Malformed syn packet cause %100 cpu and interrupts FreeBSD 9.0= release=0A= =0A= On Mar 15, 2012, at 12:49 PM, Seyit =D6zg=FCr wrote:=0A= > Today we tried to see what happens Malformed syn packets on FreeBSD 9.0 r= elease..=0A= >=0A= > Those packets rise to CPU %100 and stucks..=0A= >=0A= > listening on ix0, link-type EN10MB (Ethernet), capture size 65535 bytes= =0A= > 18:33:30.010215 IP vgn44-1-88-123-89-40.fbx.proxad.net > 85.xxx.xxx.90: t= cp=0A= > 18:33:30.010242 IP 225.74.196.88.sta.estpak.ee > 85.xxx.xxx.90: tcp=0A= > 18:33:30.010269 IP Nnov-Prospekt.71.quantum.rn > 85.xxx.xxx.90: tcp=0A= > 18:33:30.010296 IP host52-108-static.49-88-b.business.telecomitalia.it > = 85.xxx.xxx.90: tcp=0A= > 18:33:30.010325 IP 125.Red-88-1-75.dynamicIP.rima-tde.net > 85.xxx.xxx.90= : tcp=0A= >=0A= > i dont know which tool generate those packets.. but as we see i dont see = seq, flag, lenth etc.. just this ouput on tcpdump...=0A= >=0A= > Is there any kernel feature for do NOT process malformed syn packets ??= =0A= =0A= A firewall can block them before the system will see and try to process the= m as incoming traffic.=0A= =0A= Also, running tcpdump with -X will give both hex and ASCII rendition of the= packets, which would be helpful to identify what you mean by "malformed".= =0A= =0A= Regards,=0A= --=0A= -Chuck=0A= =0A=