Date: Mon, 9 Feb 1998 14:50:13 -0800 (PST) From: Dan Busarow <dan@dpcsys.com> To: "Eric C. S. Dynamic" <ecsd@transbay.net> Cc: questions@FreeBSD.ORG Subject: Re: arp question Message-ID: <Pine.UW2.3.95.980209143057.9539B-100000@cedb> In-Reply-To: <34DF6A3A.398A68D@transbay.net>
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On Mon, 9 Feb 1998, Eric C. S. Dynamic wrote: > > You're defining your ethernet aliases wrong. Try this: > > ifconfig vx0 inet a.b.c+1.2 netmask 0xffffffff alias > > Doug White | University of Oregon > > That worked. (To get the "arp -s" accepted, anyway.) > > I know this has undoubtedly gone through in thread(s) here, but > why can't I alias an interface using the netmask appropriate for that > interface? If I remember your original post correctly the first ifconfig of the interface was for the 0xfffffe00 subnet (2 C's). Is that right? That already includes the aliased ifconfig z.b.c+1.2, so you need to use a host route for the alias. > My router is on the network as two different class C's. > My host is on the network as a single 512-IP subnet. > > My notion was to define the host interface so that not only was it > primarily the 512-IP interface as required, but also so that it > was on the upper class C by itself. I could imagine that the routing > would be a bit nonplussed with this, but I could also imagine that > the routing would just say, "fine, if you want to do it that way." > > The reason for doing this is (1) that in order to aggregate the two > class C subnets into one on the router, I have to get all my remote > users to switch netmasks at once, and that's proved administratively > difficult. I can tell the router its netmask is 0xfffffe00, but once Much easier is to have the router's ethernet port use an address out of the first C (by convention, nothing more) and a netmask of 255.255.255.0, just like you only had the one C. Then add a route telling it what machine(s) to route the other C to, or 1/2 C or whatever. Let's say you have two machines on your LAN handling the second C, 126 addresses each. one is a.b.c.3, the other is a.b.c.4 On the router route add a.b.c+1.0/25 a.b.c.3 1 route add a.b.c+1.128/25 a.b.c.4 1 On the machines ifconfig inet vx0 a.b.c.3 netmask 0xffffff00 ifconfig inet vx0 a.b.c+1.1 netmask 0xffffff00 alias ifconfig inet vx0 a.b.c+1.2 netmask 0xffffffff alias ifconfig inet vx0 a.b.c+1.3 netmask 0xffffffff alias If you had a few hundred stupid (ie MS) boxes on your LAN supernetting might make sense, but when you have a few smart boxes let them deal with it. This way your users won't need to change their netmasks every time you get new address space. Turn off routed too. Dan -- Dan Busarow 714 443 4172 DPC Systems / Beach.Net dan@dpcsys.com Dana Point, California 83 09 EF 59 E0 11 89 B4 8D 09 DB FD E1 DD 0C 82 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe questions" in the body of the message
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