From owner-freebsd-stable Tue May 7 11:12:14 2002 Delivered-To: freebsd-stable@freebsd.org Received: from verdi.nethelp.no (verdi.nethelp.no [194.19.15.2]) by hub.freebsd.org (Postfix) with SMTP id A07B037B404 for ; Tue, 7 May 2002 11:12:04 -0700 (PDT) Received: (qmail 97220 invoked by uid 1001); 7 May 2002 18:11:57 +0000 (GMT) To: kudzu@tenebras.com Cc: freebsd-stable@FreeBSD.ORG Subject: Re: Unable to alias IP's in 4.5 From: sthaug@nethelp.no In-Reply-To: Your message of "Tue, 07 May 2002 10:47:46 -0700" References: <3CD81342.6090009@tenebras.com> X-Mailer: Mew version 1.05+ on Emacs 19.34.2 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Date: Tue, 07 May 2002 20:11:57 +0200 Message-ID: <97218.1020795117@verdi.nethelp.no> Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > >>What changed is that the code now enforces that you do it the right way, > >>which is to use 255.255.255.255 as the netmask for the alias IPs. That is, > >>use the normal/proper netmask for the primary IP for that NIC, then use > >>255.255.255.255 for any alias IPs on the same subnet for that NIC. > > > > > > That's rather counter-intuitive. Is that behavior mandated by > > some standard or other? > > Some things appear counter-intuitive due to poor design, while others do > because we're ignorant ;-) > > There are possible side effects to IP aliases in routing tables > and arp handling -- using a netmask of 0xffffffff was always > the proper approach, and now it is enforced. It should be noted that there is no law of nature which says it has to be done this way. I've been using Cisco routers and FreeBSD for many years, and the Cisco behavior (a secondary address on the same segment as the primary IP address uses the same netmask also) has always seemed more natural/less confusing. Steinar Haug, Nethelp consulting, sthaug@nethelp.no To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message