From owner-freebsd-net@freebsd.org Tue Dec 1 16:52:28 2015 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A4CA7A3E9E1 for ; Tue, 1 Dec 2015 16:52:28 +0000 (UTC) (envelope-from feld@FreeBSD.org) Received: from out4-smtp.messagingengine.com (out4-smtp.messagingengine.com [66.111.4.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 7474018BD for ; Tue, 1 Dec 2015 16:52:28 +0000 (UTC) (envelope-from feld@FreeBSD.org) Received: from compute6.internal (compute6.nyi.internal [10.202.2.46]) by mailout.nyi.internal (Postfix) with ESMTP id 5E03C204AE for ; Tue, 1 Dec 2015 11:52:27 -0500 (EST) Received: from web3 ([10.202.2.213]) by compute6.internal (MEProxy); Tue, 01 Dec 2015 11:52:27 -0500 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:content-type :date:from:in-reply-to:message-id:mime-version:references :subject:to:x-sasl-enc:x-sasl-enc; s=smtpout; bh=nPHLmwbQl/QfsE0 0L52cUg2O0sc=; b=RDK+7FOVIHCw7uw07ZcO+Mk/1h6O2wFkDBQj7F9MIPQhMnK lRRGewbnWSbLq49QR1afM/WGcMmVBvNu2/fFBkiQOrkUo0mvaRld1e6kbISI5/B/ QWCu4+fMB13sLT56tESoqCv1FB3M9TVsZuuVrl2Z2CDV5Ghq8dHiNFH9p4GE= Received: by web3.nyi.internal (Postfix, from userid 99) id 31E9710C769; Tue, 1 Dec 2015 11:52:27 -0500 (EST) Message-Id: <1448988747.1302736.454866425.02D98B53@webmail.messagingengine.com> X-Sasl-Enc: 1bu3gLX+lRXOn2y+vCFT/avutoPal/yWt952cFNz9V3r 1448988747 From: Mark Felder To: elof2@sentor.se Cc: "freebsd-net" , Matthew Seaman MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain X-Mailer: MessagingEngine.com Webmail Interface - ajax-b94e6169 Subject: Re: IPFW blocked my IPv6 NTP traffic Date: Tue, 01 Dec 2015 10:52:27 -0600 In-Reply-To: References: <1448920706.962818.454005905.61CF9154@webmail.messagingengine.com> <1448956697.854911427.15is5btc@frv34.fwdcdn.com> <1448982333.1269981.454734633.11BA4DB2@webmail.messagingengine.com> <565DBA5B.20203@FreeBSD.org> <1448986156.1288999.454817825.3C08D1EA@webmail.messagingengine.com> X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 01 Dec 2015 16:52:28 -0000 On Tue, Dec 1, 2015, at 10:50, elof2@sentor.se wrote: > > Not that this helps this thread to move on, but just to clarify: > > In this case, the NAT that would introduce the randomized src port would > be *your* NAT, not a NAT at pool.ntp.org. > > > Deny UDP [2604:a880:800:10::bc:c004]:123 [2001:470:1f11:1e8::2]:58285 in > via gif0 > > The blocked response came from port 123 just as expected. > > If the client truly sent out a query from src port 123, then it must have > been your NAT that picked a free random port to use for its outgoing > connection, i.e. port 58285. > The server then respond back to your NAT-IP 2001:470:1f11:1e8::2 at port > 58285. > Your NAT should receive the packet, match it against its NAT table, find > that it has indeed an ongoing UDP connection for that particular flow, so > it rewrites the dst IP and dst port to your original internal IP address > and original port (123) and send it back to the client. > > /Elof > There's no NAT involved with my IPv6. -- Mark Felder ports-secteam member feld@FreeBSD.org