Michael H. Warfield (mhw@wittsend.com) writes:
> On Mon, May 15, 2000 at 06:38:08PM -0900, Christopher E. Brown wrote:
> > On Mon, 15 May 2000, Ed Carp wrote:
>
> > > Dan Kegel (dank@alumni.caltech.edu) writes:
>
> > > > In http://www.kegel.com/mediaone.html I relate my problems when
> > > > I was assigned an address ending in .0 or .255. Even though this
> > > > was a valid address, some routers out on the internet blocked
> > > > access, assuming packets from my address were forged as part
> > > > of a smurf attack.
>
> > > No, sir, those addresses are not valid addresses, since most if not all hosts
> > > may respond to them. Witness what happens when you ping an address ending in
> > > either .0 or .255 - they are usually interpreted as broadcast addresses, NOT
> > > to be assigned to hosts.
>
>
> > This is only true in classful routing, not classless. In any
> > case (old or new), the last hop router is the one that should be
> > dropping or not dropping the packet, *never* a router somewhere in the
> > middle.
>
> It's not even true then. It's only true in the case of classful
> routing on a class C network (255.255 and 0.0 on a class B and 255.255.255
> and 0.0.0 on a Class A) or in a /24 in classless routing (as defined by
> the end router - intermediate routers can NOT make that determination).
> In the case of /25 or smaller (larger number), 255 and 0 are bad but
> so are 128 and 127 as well as others (depending on netmask number).
Did you deliberately overlook the point? It's not the routers that were my
point, it was the hosts that respond to such broadcasts.
-- Ed Carp, N7EKG erc@pobox.com 940/367-2744 cell phone http://www.pobox.com/~erc- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Tue May 23 2000 - 21:00:10 EST