From owner-freebsd-net@FreeBSD.ORG Sun Mar 30 12:11:29 2003 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 939E137B408 for ; Sun, 30 Mar 2003 12:11:29 -0800 (PST) Received: from basie.internet2.edu (basie.internet2.edu [207.75.164.22]) by mx1.FreeBSD.org (Postfix) with ESMTP id 27CC443F75 for ; Sun, 30 Mar 2003 12:11:27 -0800 (PST) (envelope-from boote@internet2.edu) Received: from localhost (localhost.localdomain [127.0.0.1]) by basie.internet2.edu (Postfix) with ESMTP id 8FAE87B4A1; Sun, 30 Mar 2003 15:11:26 -0500 (EST) Received: from internet2.edu (localhost [127.0.0.1]) by basie.internet2.edu (Postfix) with ESMTP id 2AA3C7B46E; Sun, 30 Mar 2003 15:11:25 -0500 (EST) Message-ID: <3E874F6C.A76F99E8@internet2.edu> Date: Sun, 30 Mar 2003 13:11:24 -0700 From: "Jeff W. Boote" X-Mailer: Mozilla 4.79 [en] (Windows NT 5.0; U) X-Accept-Language: en MIME-Version: 1.0 To: Hajimu UMEMOTO References: <20030326134823.A7029@jamaica.grc.nasa.gov> <20030327104649.B18679@jamaica.grc.nasa.gov> <3E838784.F2F4E330@internet2.edu> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Virus-Scanned: by AMaViS 0.3.12pre8 cc: freebsd-net@freebsd.org Subject: Re: FreeBSD 5.0 dual-stack server X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 30 Mar 2003 20:11:38 -0000 Hajimu UMEMOTO wrote: > boote> It is behaving as if the IPV6_BINDV6ONLY sockopt is set... Has the > boote> "default" value for this changed? > > Yes. > BTW, IPV6_BINDV6ONLY has been superseded by IPV6_V6ONLY. Ah - thanks. > boote> Is it recommended that any server that wants to bind to the dual-stack > boote> needs to make sure this sockopt is unset? I am not doing that... > > Yup, where you can do it, you should do so. > However, I suggest opening two sockets, one is for IPv6 and the other > is for IPv4, instead of using IPv4-mapped IPv6 address. Hmm. So the trade-off is calling select or using IN6_IS_ADDR_V4MAPPED? (My applications need to understand the addresses at a pretty detailed level anyway - I'll probably stick to the dual-stack method.) > boote> I just found the net.inet6.ip6.bindv6only sysctl variable doing a web > boote> search... What is the default value for this sysctl on 5.0? > > net.inet6.ip6.bindv6only=1 by default on 5-CURRENT. This seems to contradict the recommendation in RFC 3493 (which I realize is only informational)... I've been doing a web search to try and find some kind of record for the rational used for making this default to v6only. I haven't found anything substantial yet. Does anyone on this list know why? (I'm guessing there must be a good reason - and if so, I want to make sure I'm dealing with those issues in my applications.) > boote> (I guess I may need to install 5.0 on a box, and stop bothering > boote> others...) > > You don't need to install 5.0. You can simply get same effect by > setting net.inet6.ip6.bindv6only=1. Thanks! jeff