Re: IPv6 problems.... (dhcpcd weirdness, rshd fails, etc.)

> It seems silly to me that the kernel can't figure this out itself
> when it knows the address explicitly and completely as it does in
> this case.  I'm pretty sure you can't have the same address on two
> different interfaces no matter what family they belong to.

Um, I _think_ you can have link-local addresses which are identical
except for the scope tag on different interfaces.  But then, you can,
as of 5.2, have the same IPv4 address on two different interfaces at
the same time; ifconfig is content to set them.  I don't know what
might break; I suspect routing would fall over in some respect.  The
same is probably true of v6 as well, except that the scope tags keep
routing from getting confused; when I set fe80::1:2:3/64 on both re0
and re1, the routing table contains distinct routes for them:

fe80::/10                          ::1                            UGRS        0        0      -  lo0
fe80::%re0/64                      link#1             UC          0        0      -  re0
fe80::1:2:3%re0                    68:ed:a4:1c:a0:f0  UHL         0        0      -  lo0
fe80::6aed:a4ff:fe1c:a0f0%re0      68:ed:a4:1c:a0:f0  UHL         0        0      -  lo0
fe80::%re1/64                      link#2             UC          0        0      -  re1
fe80::1:2:3%re1                    68:ed:a4:1c:a0:f1  UHL         0        0      -  lo0
fe80::6aed:a4ff:fe1c:a0f1%re1      68:ed:a4:1c:a0:f1  UHL         0        0      -  lo0
fe80::%lo0/64                      fe80::1%lo0                    U           0        0      -  lo0
fe80::1%lo0                        link#3             UHL         0        0      -  lo0

in contrast to the v4 case, where the routing table contains only one
route (in my case it was for re0; I don't know whether this was because
it was the one I set first or the lower ifindex or what).

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