On Fri, Jul 25, 2014 at 03:38:39PM -0500, Brian Wood wrote:
> Andrew Lunn writes:
> 
> >> One difference in working with BSD is that I have to use
> >> ::1 in order to tell the middle tier that the back tier is running
> >> on the same machine.  On Linux I have to use 127.0.0.1.
> >> Are there any conditional compilation macros for BSD so I
> >> could write
> >
> > ::1 should also work on linux, so long as you have IPv6 enabled.
> 
> I've run into something related now.   Using sockstat I figured out
> that my back tier's listening socket was a tcp6 socket.  I'm able to
> connect to the socket when running another process on the same
> machine.  But if I try to connect using an Ubuntu machine, I get
> connection refused.   I guess it doesn't have IPv6 enabled.

That would be pretty unusual now a days, having IPv6 disabled. What is
more likely is that IPv6 is enabled, but the interfaces only have link
local scope addresses. You need something to allocate you IPv6
addresses, either manually, or using dhcpv6 or your router advertising
prefix and then linux will automagically put a suitable IPv6 address
on the interfaces.

> From what I could tell, there's more interest in figuring out how to
> disable IPV6 than enable it.

http://tech.slashdot.org/story/14/07/24/1835244/comcast-carrying-1tbits-of-ipv6-internet-traffic

Things have started to change recently. Its getting to the state that
for the average user, it just works, and it just works without them
even knowing it.

     Andrew