FreeBSD 5.0 dual-stack server

[Jeff W. Boote]

Hajimu UMEMOTO wrote:
> boote> It is behaving as if the IPV6_BINDV6ONLY sockopt is set... Has the
> boote> "default" value for this changed?
> 
> Yes.
> BTW, IPV6_BINDV6ONLY has been superseded by IPV6_V6ONLY.

Ah - thanks.

> boote> Is it recommended that any server that wants to bind to the dual-stack
> boote> needs to make sure this sockopt is unset? I am not doing that...
> 
> Yup, where you can do it, you should do so.
> However, I suggest opening two sockets, one is for IPv6 and the other
> is for IPv4, instead of using IPv4-mapped IPv6 address.

Hmm. So the trade-off is calling select or using IN6_IS_ADDR_V4MAPPED?
(My applications need to understand the addresses at a pretty detailed
level anyway - I'll probably stick to the dual-stack method.)
 
> boote> I just found the net.inet6.ip6.bindv6only sysctl variable doing a web
> boote> search... What is the default value for this sysctl on 5.0?
> 
> net.inet6.ip6.bindv6only=1 by default on 5-CURRENT.

This seems to contradict the recommendation in RFC 3493 (which I realize
is only informational)... I've been doing a web search to try and find
some kind of record for the rational used for making this default to
v6only. I haven't found anything substantial yet. Does anyone on this
list know why? (I'm guessing there must be a good reason - and if so, I
want to make sure I'm dealing with those issues in my applications.)

> boote> (I guess I may need to install 5.0 on a box, and stop bothering
> boote> others...)
> 
> You don't need to install 5.0.  You can simply get same effect by
> setting net.inet6.ip6.bindv6only=1.

Thanks!
jeff