is use of IF-ID 0 "clean"
Dear WG-folks, out of curiosity and because I got asked this question, here we go: Is the use of "0" as the interface ID in an IPv6 network "clean"? I haven't found any indication that "0" is reserved (as in IPv4), or should not be used, but there's a lingering feeling that it may cause trouble, somewhere, somehow. Any input appreciated, tia, Wilfried.
On 6/20/14, Wilfried Woeber <Woeber@cc.univie.ac.at> wrote:
Dear WG-folks,
out of curiosity and because I got asked this question, here we go:
Is the use of "0" as the interface ID in an IPv6 network "clean"? I haven't found any indication that "0" is reserved (as in IPv4), or should not be used, but there's a lingering feeling that it may cause trouble, somewhere, somehow.
Using all-zero IID forms a subnet-router anycast address: http://tools.ietf.org/html/rfc4291#section-2.6.1 Also, I've read about linux hosts responding to fe80:: if it is configured on any link on the router (though reads like a clear bug to me, and maybe fixed already). --a
Any input appreciated, tia, Wilfried.
Hi folks, Andrew 👽 Yourtchenko <ayourtch@gmail.com> writes:
Using all-zero IID forms a subnet-router anycast address:
http://tools.ietf.org/html/rfc4291#section-2.6.1
Also, I've read about linux hosts responding to fe80:: if it is configured on any link on the router (though reads like a clear bug to me, and maybe fixed already).
well, any router is supposed to listen on that anycast address, so enabling that address when you turn on IPv6 forwarding does make some sense. Cheers, Benedikt -- Benedikt Stockebrand, Stepladder IT Training+Consulting Dipl.-Inform. http://www.stepladder-it.com/ Business Grade IPv6 --- Consulting, Training, Projects BIVBlog---Benedikt's IT Video Blog: http://www.stepladder-it.com/bivblog/
On 21 Jun 2014, at 16:09, Benedikt Stockebrand <bs@stepladder-it.com> wrote:
Hi folks,
Andrew 👽 Yourtchenko <ayourtch@gmail.com> writes:
Using all-zero IID forms a subnet-router anycast address:
http://tools.ietf.org/html/rfc4291#section-2.6.1
Also, I've read about linux hosts responding to fe80:: if it is configured on any link on the router (though reads like a clear bug to me, and maybe fixed already).
well, any router is supposed to listen on that anycast address, so enabling that address when you turn on IPv6 forwarding does make some sense.
My sentence was about linux box not being a host.. But now that you mention it - sounds plausible that the folks I heard it from had linux host doing forwarding and forgot about it - makes sense indeed then and of course not a bug. --a
Cheers,
Benedikt
-- Benedikt Stockebrand, Stepladder IT Training+Consulting Dipl.-Inform. http://www.stepladder-it.com/
Business Grade IPv6 --- Consulting, Training, Projects
BIVBlog---Benedikt's IT Video Blog: http://www.stepladder-it.com/bivblog/
Hi, RFC 4291 does define all-zeros interface ID addresses as a router-anycast address and while it's not explicitly prohibited to use it as an interface ID address, it is strongly discouraged. (This also carries over into other RFCs and BCP documents.) The only case I know of that clearly advocates (even mandates) the use of all-zeros interface ID addresses is RFC 6164 about using /127 networks on point-to-point links where supported. Apart from point-to-point links I tend to stay away from all-zeros addresses in order to comply with as many IPv6 RFCs as possible. ;-) // H -----Original Message----- From: ipv6-wg-bounces@ripe.net [mailto:ipv6-wg-bounces@ripe.net] On Behalf Of Andrew Yourtchenko Sent: 22. juni 2014 15:32 To: Benedikt Stockebrand Cc: Woeber@cc.univie.ac.at; ipv6-wg@ripe.net Subject: Re: [ipv6-wg] is use of IF-ID 0 "clean"
On 21 Jun 2014, at 16:09, Benedikt Stockebrand <bs@stepladder-it.com> wrote:
Hi folks,
Andrew 👽 Yourtchenko <ayourtch@gmail.com> writes:
Using all-zero IID forms a subnet-router anycast address:
http://tools.ietf.org/html/rfc4291#section-2.6.1
Also, I've read about linux hosts responding to fe80:: if it is configured on any link on the router (though reads like a clear bug to me, and maybe fixed already).
well, any router is supposed to listen on that anycast address, so enabling that address when you turn on IPv6 forwarding does make some sense.
My sentence was about linux box not being a host.. But now that you mention it - sounds plausible that the folks I heard it from had linux host doing forwarding and forgot about it - makes sense indeed then and of course not a bug. --a
Cheers,
Benedikt
-- Benedikt Stockebrand, Stepladder IT Training+Consulting Dipl.-Inform. http://www.stepladder-it.com/
Business Grade IPv6 --- Consulting, Training, Projects
BIVBlog---Benedikt's IT Video Blog: http://www.stepladder-it.com/bivblog/
Thanks to all of you who provided input and feeback! Wilfried.
participants (5)
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Andrew Yourtchenko -
Andrew 👽 Yourtchenko
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Benedikt Stockebrand -
Lans, Henrik Ove -
Wilfried Woeber