[zeromq-dev] [PATCH] IPv6 changes to 4.0

Steven McCoy steven.mccoy at miru.hk
Fri Aug 26 10:22:38 CEST 2011

On 26 August 2011 14:06, Steven McCoy <steven.mccoy at miru.hk> wrote:

> On 26 August 2011 14:02, Martin Sustrik <sustrik at 250bpm.com> wrote:
>> On 08/26/2011 07:25 AM, Steven McCoy wrote:
>>  Then my Linux box ends up looking like this:
>>> eth0      Link encap:Ethernet  HWaddr 00:14:5e:bd:6d:da
>>>           inet addr:  Bcast:  Mask:
>>>           inet6 addr: 2002:dce8:d28e:0:214:5eff:**febd:6dda/64
>>> Scope:Global
>>>           inet6 addr: fe80::214:5eff:febd:6dda/64 Scope:Link
>>>           inet6 addr: 2002:dce8:d28e::31/64 Scope:Global
>>>           UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
>>> lo        Link encap:Local Loopback
>>>           inet addr:  Mask:
>>>           inet6 addr: ::1/128 Scope:Host
>>>           UP LOOPBACK RUNNING  MTU:16436  Metric:1
>>> That's trying to give a static IPv6 to each host with the
>>> 2002:dce8:d28e:: prefix but getting an
>>> additional auto-configuration address fromin.ripngd because that's
>>> lovely Solaris.
>> So is it Linux or Solaris?
>> Btw, is having two global addresses on a same interface OK from the point
>> of view of IPv6 specs?
> First list is SPARC/Solaris second is x64/Linux.  Running in.ripng
> implements IPv6 auto-configuration for the LAN segment hence doling out the
> additional address.
> That's the only way to configure IPv6 in Solaris.
> Conversely if you don't add on static IPv6 addressing then you would only
> have one global-scope address.  So you could say I am making it worse.
Go figure, following the same instructions as last year and now IPv6
configuration remains correct and persistent across reboots without
auto-configuration enabled.

You can also add the "preferred" flag to a particular interface which is
probably the only option available for detecting the address to use.

lo0: flags=2001000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv4,VIRTUAL> mtu 8232
index 1
        inet netmask ff000000
eri0: flags=1000843<UP,BROADCAST,RUNNING,MULTICAST,IPv4> mtu 1500 index 2
        inet netmask ffffff00 broadcast
lo0: flags=2002000849<UP,LOOPBACK,RUNNING,MULTICAST,IPv6,VIRTUAL> mtu 8252
index 1
        inet6 ::1/128
eri0: flags=2104841<UP,RUNNING,MULTICAST,DHCP,ROUTER,IPv6> mtu 1500 index 2
        inet6 fe80::203:baff:fe4e:6cc8/10
eri0:1: flags=402100841<UP,RUNNING,MULTICAST,ROUTER,IPv6,PREFERRED> mtu 1500
index 2
        inet6 2002:dce8:d28e::36/64

Which should match this:

/usr/include/net/if.h:#define   IFF_PREFERRED   0x0400000000    /* Prefer as
source address */

There is no equivalent in Linux though, this page hints at a similar


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