It's Ars Tech's turn to bang the IPv4 exhaustion drum

Iljitsch van Beijnum iljitsch at
Wed Aug 20 13:57:46 CDT 2008

On 20 aug 2008, at 20:34, Crist Clark wrote:

> On a "true" P-to-P link, there is no netmask, no? A netmask is a
> concept that applies to broadcast media, like Ethernet. Even if
> you only have two hosts on an Ethernet link, it's not really
> P-to-P in the strict sense.

An interface needs a prefix length (subnet mask for those of us stuck  
in the '90s) so the system knows which addresses are directly  
connected through the interface in question. Whether the link is point- 
to-point, broadcast or NBMA doesn't matter for that purpose.

> But as for how ND works over a P-to-P, the FreeBSD stack seems
> to be a little odd.


> But despite all of that, it all works pretty sweetly.

There have been compatibility issues with PPP for IPv6 in the past  
because some implementations would do ND and others wouldn't...

More information about the NANOG mailing list