evil ipv6 bit?

Fri Jan 26 17:35:45 UTC 2018

On Fri 2018-Jan-26 15:55:58 +0000, Saku Ytti <saku at ytti.fi> wrote:

>On 26 January 2018 at 03:50, Baldur Norddahl <baldur.norddahl at gmail.com> wrote:
>
>
>> I just now discovered this:
>>
>> google.com: 2a00:1450:400e:807::200e
>>
>> That address works fine. But then I changed that one bit in the address:
>> 2a00:1450:400e:8807::200e and voila, the router drops the packet.
>>
>> Now I am stumbled. What could the 49th bit in the destination IPv6 address
>> field in a packet mean to the router, that would make it drop the packet?
>
>Are you sure it is dropped? Can you see some drop counter increase?
>Have you observed nothing coming out from any port?
>
>My guess is bad memory, and that bit is statically set or statically
>unset and cannot be changed. Might cause CRC error, IP checksum error
>or just mangled packet coming out of the router
>
>-- 
>  ++ytti

There was also this example from a while ago:

*Juniper MX80 strange dst MAC address behavior*
https://mailman.nanog.org/pipermail/nanog/2017-November/092954.html

And then this:

*Forwarding issues related to MACs starting with a 4 or a 6 (Was: [c-nsp] 
Wierd MPLS/VPLS issue)*
https://mailman.nanog.org/pipermail/nanog/2016-December/089395.html

Those are both related to _MACs_, though, rather than IPs.

-- 
Hugo Slabbert       | email, xmpp/jabber: hugo at slabnet.com
pgp key: B178313E   | also on Signal
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