[c-nsp] IP unnumbered question. Are isp's using this alot?

[Gert Doering]

Hi,

On Wed, Jun 22, 2005 at 10:23:48PM -0700, Ted Mittelstaedt wrote:
> [..] it is perfectly fine to use private numbers.  

No, it's not, and it doesn't get any more true if repeated a couple
of times.

Using private IPs for transit links makes the routers (at least all products 
in widespread use today) generate packets with RFC1918 source IPs, and
this is a violation of RFC1918 - "do not send packets source from these
IPs out into the wild".

This breaks path MTU discovery, traceroute, and other useful ICMP
features.  If you *want* to break that, then say so, but don't abuse
RFC1918 space for it.

gert
-- 
Gert Doering
Mobile communications ... right now writing from * Isola dei Gabbiani *