Manual Configuration of Interface ID

Chad Kissinger chad at
Mon Dec 20 18:27:53 CET 2010

So, you are saying that I can choose any 64 bit combination for the Interface ID as long as the 71st and 72nd bits are 0.  Right?  

chad kissinger  |  founder-vp  |  onramp access, llc 
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-----Original Message-----
From: at [ at] On Behalf Of Daniel Roesen
Sent: Monday, December 20, 2010 11:11 AM
To: ipv6-ops at
Subject: Re: Manual Configuration of Interface ID

On Mon, Dec 20, 2010 at 10:05:58AM -0600, Chad Kissinger wrote:
> However, after many days of reading, I cannot find any place that
> specifically details the method one would use to identify suitable
> ranges to choose from for a manually configured Interface ID or a
> pool of such IDs.  Is it as simple as setting the 71st and 72nd
> bit and avoiding Anycast addresses?

Those two bits have to be UNSET for non-globally-unique unicast
address (IPv6 host part uses Modified EUI-64, which differs from
standard EUI-64 in having the U/L bit inverted to make locally made-up
"vanity" addresses better readable because compressible).

Best regards,

CLUE-RIPE -- Jabber: dr at -- dr at IRCnet -- PGP: 0xA85C8AA0

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