Date: Sun, 30 Mar 2003 13:11:24 -0700 From: "Jeff W. Boote" <boote@internet2.edu> To: Hajimu UMEMOTO <ume@mahoroba.org> Cc: freebsd-net@freebsd.org Subject: Re: FreeBSD 5.0 dual-stack server Message-ID: <3E874F6C.A76F99E8@internet2.edu> References: <20030326134823.A7029@jamaica.grc.nasa.gov> <20030327104649.B18679@jamaica.grc.nasa.gov> <3E838784.F2F4E330@internet2.edu> <yge4r5kvfvg.wl%ume@mahoroba.org>
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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 BTW, IPV6_BINDV6ONLY has been superseded by IPV6_V6ONLY.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
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