From owner-freebsd-ipfw@FreeBSD.ORG Thu Jul 16 19:50:53 2009 Return-Path: Delivered-To: freebsd-ipfw@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id BDFF6106568C for ; Thu, 16 Jul 2009 19:50:53 +0000 (UTC) (envelope-from dima_bsd@inbox.lv) Received: from smtp2.apollo.lv (smtp2.apollo.lv [80.232.168.229]) by mx1.freebsd.org (Postfix) with ESMTP id 4B13B8FC1D for ; Thu, 16 Jul 2009 19:50:53 +0000 (UTC) (envelope-from dima_bsd@inbox.lv) X-Cloudmark-Score: 0.000000 [] X-Virusscan: Clamd Received: from [87.110.108.74] ([87.110.108.74] verified) by smtp2.apollo.lv (CommuniGate Pro SMTP 5.2.10) with ESMTP id 455753913; Thu, 16 Jul 2009 22:50:52 +0300 From: Dmitriy Demidov To: Chuck Swiger Date: Thu, 16 Jul 2009 22:50:51 +0300 User-Agent: KMail/1.9.10 References: <200907142355.34973.dima_bsd@inbox.lv> <200907162219.04986.dima_bsd@inbox.lv> <2CE3CD12-D430-4378-92C1-591227888428@mac.com> In-Reply-To: <2CE3CD12-D430-4378-92C1-591227888428@mac.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200907162250.51585.dima_bsd@inbox.lv> Cc: freebsd-ipfw@freebsd.org Subject: Re: ipfw nat and localy initiated UDP traffic (bad udp cksum) X-BeenThere: freebsd-ipfw@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: IPFW Technical Discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Jul 2009 19:50:54 -0000 On Thursday 16 July 2009, Chuck Swiger wrote: > On Jul 16, 2009, at 12:19 PM, Dmitriy Demidov wrote: > > Update about this issue. > > There is somthing wrong with UDP pass through - ipfw nat makes it > > "bad cksum". > > tcpdump receives local network traffic before the checksums are > computed (especially if hardware checksums are enabled); this is a non- > issue, although you could confirm by sniffing the traffic from an > external machine like a laptop. > > Regards, Wow! :) Thank you Chuck for this hint! I catch the problem! My em0 have offload options on, so I turned them off and now all is working as expected. before: === em0: flags=8843 metric 0 mtu 1500 options=9b ether 00:20:ed:91:97:93 inet 87.110.108.74 netmask 0xfffffe00 broadcast 255.255.255.255 media: Ethernet autoselect (100baseTX ) status: active === after: === em0: flags=8843 metric 0 mtu 1500 options=98 ether 00:20:ed:91:97:93 inet 87.110.108.74 netmask 0xfffffe00 broadcast 255.255.255.255 media: Ethernet autoselect (100baseTX ) status: active === dmesg | grep em0 === em0: port 0xa000-0xa03f mem 0xdb100000-0xdb11ffff irq 21 at device 9.0 on pci2 em0: [FILTER] em0: Ethernet address: 00:20:ed:91:97:93 === pciconf -lv === em0@pci0:2:9:0: class=0x020000 card=0x30138086 chip=0x100e8086 rev=0x02 hdr=0x00 vendor = 'Intel Corporation' device = 'Gigabit Ethernet Controller (82540EM)' class = network subclass = ethernet === Do this looks like a bug (em drivers, nat, etc...) or not? Should I make new PR for this problem?