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).
> ---
> As folks might have suspected, not much survives except roaches,
> and they don't carry large enough packets fast enough...
> --About the Internet and nuclear war.
Mike
-- Michael H. Warfield | (770) 985-6132 | mhw@WittsEnd.com (The Mad Wizard) | (770) 331-2437 | http://www.wittsend.com/mhw/ NIC whois: MHW9 | An optimist believes we live in the best of all PGP Key: 0xDF1DD471 | possible worlds. A pessimist is sure of it!- 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