From owner-freebsd-hackers Sat Aug 23 12:08:52 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id MAA09689 for hackers-outgoing; Sat, 23 Aug 1997 12:08:52 -0700 (PDT) Received: from gvr.gvr.org (root@gvr.gvr.org [194.151.74.97]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id MAA09681 for ; Sat, 23 Aug 1997 12:08:47 -0700 (PDT) Received: (from guido@localhost) by gvr.gvr.org (8.8.6/8.8.5) id VAA06497; Sat, 23 Aug 1997 21:08:41 +0200 (MET DST) From: Guido van Rooij Message-Id: <199708231908.VAA06497@gvr.gvr.org> Subject: Re: broadcast question In-Reply-To: <19970823143813.EY59755@uriah.heep.sax.de> from J Wunsch at "Aug 23, 97 02:38:13 pm" To: joerg_wunsch@uriah.heep.sax.de Date: Sat, 23 Aug 1997 21:08:41 +0200 (MET DST) Cc: FreeBSD-hackers@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL28 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk J Wunsch wrote: > As Guido van Rooij wrote: > > > If I have a host in a subnetted C-net, say 192.1.1.0/28 > > and I send an icmp echo request to the broadcast address of the C-net > > (so NOT to 192.1.1.15) the 2.1.7 stack does send an echo reply > > but the 2.2 stack does not. > > So an all-subnets directed broadcast seems to be ignored on 2.2 > > stacks...I think this broken, yet fail to see where it was broken. > > I think 2.1.x was broken. What is an ``all-subnets'' broadcast in a > CIDR world? Forget about class A/B/C, forget the term `subnet', they > don't exist anymore. (*) The address 192.1.1.255 is not in any way a > valid broadcast address for net 192.1.1.0/28, it's a valid broadcast > address for 192.1.1.128/25, or maybe for 192.1.1.240/28 (which are > entirely different networks from 192.1.1.0/28). I don't agree. See the first Stevens book. There actually are two kinds of broadcasts. Anyway: even if it is a bug, I still can't find where it was fixed. This makes me suspicious. > > (*) The only meaning of the historic classes A/B/C that does still > exist is that they determine the default netmask if nothing else has > been specified in ifconfig(8), or route(8), etc. This can sometimes > be convenient to type. > > 255.255.255.255 should work, i believe. > > I'm surprised 2.1.x was still broken in this respect. At least 2.1 and 2.2 and higher differ here ;-) -Guido