[ipv6hackers] IPv6 source address selection on Linux

Sander Smeenk ssmeenk at freshdot.net
Thu Jul 19 16:41:59 CEST 2012

Quoting Romain Boissat (rboissat at lv0.in):

> > Could someone provide me with clue on how i can force traffic on my
> > server going to 2001:db8::1 to *always* source from the configured ULA
> > address fded:e128:5900::1 ?
> You can this little hack to all other IPv6 addresses:
> ip addr change $IP6_ADDR/$NETMASK dev $NIC preferred_lft 0

No i can't. As i stated in my original email.
Although i might have been more clear on that subject:

| Now there's really a lot of references TO that RFC but i was unable to
| find any workable examples on how to set this up. FIDDLING WITH

... because if i set the preferred_lft for the public routable
2001:db8:: ip to 0, it also sources fded:e128:5900::1 for every other
address on the public internet. I want it to only source from
fded:e128:5900::1 when connecting to 2001:db8::1 (which is on the same
L2 network, and is why i need this so bad). It should use its public
routable IPv6 address on all other occasions.

Thanks though,
| "What allergies do you have?" "That would be fire. Makes my skin turn
| red or black and it often oozes and blisters after exposure."
| 4096R/20CC6CD2 - 6D40 1A20 B9AA 87D4 84C7  FBD6 F3A9 9442 20CC 6CD2

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