IPv6 aliases on FreeBSD 10

[Jon Radel]

On 10/23/14, 1:19 AM, pepe wrote:
> prefix 128 didn't work either. only first real address is working. none of
> the aliases work with 48, 64 or 128...
> our network is 2001:14b8:1801::/48 so that prefixlen 48 is right for ::1
> address isn't it? and well, it works so
> I think it is right...
>

It would be rather unusual to have a /48 there.  There are many things 
in IPv6 that assume you're using a /64 network on each LAN segment / 
collision domain / however-you-want-to-think-of-it.  So while, in some 
senses, using a /48 there isn't *wrong*, after all, one might need to 
have 1.208 x 10^24 addresses on a single LAN segment [but so much else 
would break], in your case it's probably wrong.

Things will probably go more smoothly in general if you use 
IPv6-think:   You were assigned 2^16 (65,536) networks (each a /64).   
You were *not* assigned 2^80 addresses.  (Obviously you were actually 
assigned 2^80 addresses, but that's really not a useful way to think of 
IPv6 addresses when planning your network.)

Assign a /64 to the network this machine is connected to.  Obviously 
other equipment has to play along and have a matching prefix length.

You might also want to show us what is in your rc.conf, not just what 
ifconfig reports.  Here's an example from an 8.3 server:

ipv6_ifconfig_fxp0="2001:470:880a:5237::10:1 prefixlen 64"
ipv6_ifconfig_fxp0_alias0="2001:470:880a:5237::12:1 prefixlen 128"
ipv6_ifconfig_fxp0_alias1="2001:4830:1707:5237::10:1 prefixlen 64"
ipv6_ifconfig_fxp0_alias2="2001:4830:1707:5237::12:1 prefixlen 128"
ipv6_defaultrouter="2001:470:880a:5237::1"

That works fine.

--Jon Radel
jon at radel.com


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