From owner-freebsd-net Thu Mar 25 15:25:52 1999 Delivered-To: freebsd-net@freebsd.org Received: from noc.demon.net (server.noc.demon.net [193.195.224.4]) by hub.freebsd.org (Postfix) with ESMTP id A74BC15265 for ; Thu, 25 Mar 1999 15:25:39 -0800 (PST) (envelope-from fanf@demon.net) Received: by noc.demon.net; id XAA04603; Thu, 25 Mar 1999 23:25:18 GMT Received: from fanf.noc.demon.net(195.11.55.83) by inside.noc.demon.net via smap (3.2) id xma004570; Thu, 25 Mar 99 23:25:09 GMT Received: from fanf by fanf.noc.demon.net with local (Exim 1.73 #2) id 10QJUr-0003NB-00; Thu, 25 Mar 1999 23:25:09 +0000 To: net@freebsd.org From: Tony Finch Subject: Re: IP alias configuration for high availability Newsgroups: chiark.mail.freebsd.net In-Reply-To: <4.1.19990323134009.0099fe10@mail.dnai.com> Organization: Deliberate Obfuscation To Amuse Tony Message-Id: Date: Thu, 25 Mar 1999 23:25:09 +0000 Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Mike Thompson wrote: > >The idea is that first network address for a server would be >fixed on the reserved IP addresses of 192.168.xxx.xxx. These >fixed addresses would be used for private communication >between the various servers. > >The other addresses used by each server would be from the >Internet IP address block assigned from our ISP (example >209.185.152.1 thru 209.185.152.20). > >With such a configuration we hope to be able to hot swap >servers among the various Internet IP addresses for system >maintenance and emergency situations for high availability. > >From my testing it seems everything works pretty well. I have >found that I need to manually break the association between >an IP address and ethernet address on the servers by using the >"arp" utility. You can avoid the need to fiddle with arp and ifconfig by setting up the alias on the server's loopback interface. You then control which servers are live by changing the routes on the router; the servers don't need to be told what's going on. To set up a server: ifconfig ed0 inet 192.168.0.1 netmask 255.255.255.0 ifconfig lo0 inet 209.185.152.1 netmask 255.255.255.255 alias On the router: route add -host 209.185.152.1 192.168.0.1 Tony. -- f.a.n.finch dot@dotat.at fanf@demon.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message