From owner-freebsd-net@freebsd.org Tue Dec 1 16:09:18 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 2933CA3DD0B for ; Tue, 1 Dec 2015 16:09:18 +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 EFBFD1172 for ; Tue, 1 Dec 2015 16:09:17 +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 F06E92082F for ; Tue, 1 Dec 2015 11:09:16 -0500 (EST) Received: from web3 ([10.202.2.213]) by compute6.internal (MEProxy); Tue, 01 Dec 2015 11:09:16 -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=7ZpbDt1qDb/xez5 D0VJF0FoOzeo=; b=tpY4BF2VaUqkSty5n5KCVMbywYCTxycFqrwGBdvW3l5XxQI 1OJ9x0IDnNWGsPL7wEwHEsZ1/1lOuqPEGVh5SQkFlOy5l07H811t/irU/c5/AiN7 hCkh7daNWcIpgAOoV9d4wtEGWk8NoR8xsDIe/Q8aGqPj+YcINE5ETI2HfDlY= Received: by web3.nyi.internal (Postfix, from userid 99) id CACDE10C46A; Tue, 1 Dec 2015 11:09:16 -0500 (EST) Message-Id: <1448986156.1288999.454817825.3C08D1EA@webmail.messagingengine.com> X-Sasl-Enc: lknEcwEwnpBItc1i13lzGcyNfn/YZzHdKSKvXcW0tU4k 1448986156 From: Mark Felder To: elof2@sentor.se, Matthew Seaman Cc: "freebsd-net" 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 10:09:16 -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> 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 16:09:18 -0000 On Tue, Dec 1, 2015, at 09:53, elof2@sentor.se wrote: > > On Tue, 1 Dec 2015, Matthew Seaman wrote: > > > On 2015/12/01 15:05, Mark Felder wrote: > >> Notice how almost all of them are port 123 on both sides, but a few of > >> them are not. Why? The RFC says that NTP is supposed to be using port > >> 123 as both the source and destination port, but I clearly have > >> something happening on port 16205. Is something screwy with ntpd in > >> CURRENT? > > > > NTP not using port 123 as the source port usually indicates that it is > > behind a NAT gateway at the other end. It's harmless and fairly common. > > ...or simply that it is a ntp *client* like ntpdate, and not a daemon. > Clients often use a random source port, while ntpd use source port 123. > I wouldn't expect something in pool.ntp.org to be behind NAT and this wasn't an ntp client like ntpdate, but those are both interesting scenarios. Perhaps I'm just naive and they have a good reason for using NAT in front of that NTP server. -- Mark Felder ports-secteam member feld@FreeBSD.org