(usagi-users 03757) Re: ipv6 routing processing

On Wed, Oct 04, 2006 at 03:52:01PM -0700, jackc wrote :
> a local compadre asserts that in ipv4, when interfaces are set with 
> addresses,
> the kernel sets up some default routes so that 2 boxes on a lan could
> chat with no router n the picture.  i assume his assertion is valid, 
> yell if not.

No. The kernel never sets up any default route implicitly (unless you
configure the interface to have a 0.0.0.0 as a netmask, which nobody
normally does).

AFAIK, this feature never existed in IPv4, and was removed from IPv6 as
it was found to be harmful (in Linux, it was removed starting with
kernel 2.6.9).

> now, ipv6. here it seems that when we assign a global address to an 
> interface,
> no routing to that interface is done anywhere. so, i start up with 2 
> units on
> a lan, each with link local addresses, and i can ping6 between them.
>
> however, as soon as i assign global addresses to each unit on the lan,
> both ping6 & ftp are saying, network unreachable.

No, it works fine. Of course the global addresses have to have the same
network prefix, and nodes have to be on the same logical network
segment.

You obviously messed up.

> so, is it a requirement that ipv6 networks have an ipv6 router on each 
> lan segment
> to provide routing information to the lan units?

Of course not.

> or is there some chunk of userland code that handles routing that i am 
> so far unaware of?

Neither.

> any related clues or urls?

-- 
Rémi Denis-Courmont
http://www.remlab.net/