Simple IPv6 question [Was: Re: IPv6 site local EUI-64 adresses and jails]

Emanuel Strobl Emanuel.strobl at
Mon Aug 15 18:51:31 GMT 2005

Am Freitag, 12. August 2005 21:24 CEST schrieb Emanuel Strobl:
> Am Freitag, 12. August 2005 20:53 CEST schrieb Emanuel Strobl:
> > Hi all,
> >
> > I'm quiet new to IPv6 so I'd like to ask some questions:
> Here are two more:
> How do I use the eui64 option of ifconfig? 'ifconfig fxp0 inet6
> fe80:0:0:0:eui64 ' doesn't work!
> What's the meaning of the "%fxp0" tail of the ifconfig output for the
> inet6 address?

Dear inet6 guys,

I don't know the kind of addresses FreeBSD uses for autoconfigured 
link-local addresses.
For example: fe80::20e:cff:fe34:2bf8%em0

What the hack is %em0 ??? Interestingly I can use this address, but ping6 
fe80::20e:cff:fe34:2bf8 doesn't work....
The Handbook doesn't clarify this mysterious address. Is it FreeBSD 

Thanks in andvance, I posted this also to current@ since I got no answer 
from questions@


> Thanks,
> -Harry
> > So far I know how to generate s site-local address on basis of the MAC
> > address of the interface. That's what FreeBSD does itself for INET6
> > enabled kernels.
> > Now in the 24-16-24 scheme of th interface id part of the IPv6
> > address, the 16 bits were inserted with the value FFFE. And bit 57 was
> > changed to one! Why???? What if it is alread one? Or isn't tehre any
> > vendor who can have bit 41 of his MAC 1?
> > Now I want to use a dedicated interface, which is in a different
> > subnet, for 5 jails. How do I do that if I want to keep the MAC
> > relation and if I'm not allewd to change the FFFE insert? It isn't
> > possible then, is it? What should I do instead? Invent my own 64-bit
> > scheme?
> >
> > I hope you understand my questions, thanks a lot in advance,
> >
> > -Harr
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