[wellylug] Routing the unroutable, aka 10.0.0.0/8

[Ewen McNeill]

On 26/09/14 15:50, Christian Gagneraud wrote:
> Not only Firewall, what about BGP and co? How do you announce to the
> world that 10.X.Y.Z belongs to your AS, when these IP address are
> supposed to be private?

You don't.  At least not to the Internet.  But router linknets (ie, the 
hop-by-hop links between routers that talk directly to each other) don't 
need to be reachable from anywhere else.  Even ISPs that still use 
globally unique addresses for those will often either not advertise the 
linknet block, or firewall at their border.

(You see it in traceroutes without it being routed because the 
traceroute "got to here" packets only need a route to the destination -- 
ie, your system that initiated the traceroute.  Even now relatively 
little checks for valid sources.)

Ewen