Date: Fri, 25 Sep 1998 11:16:51 -0700 From: Ulf Zimmermann <ulf@Alameda.net> To: "Jeffrey J. Mountin" <jeff-ml@mountin.net>, Bill Vermillion <bill@bilver.magicnet.net>, freebsd-isp@FreeBSD.ORG Subject: Re: Routing problem Message-ID: <19980925111651.D22112@Alameda.net> In-Reply-To: <3.0.3.32.19980925121618.00714074@207.227.119.2>; from Jeffrey J. Mountin on Fri, Sep 25, 1998 at 12:16:18PM -0500 References: <199809240148.VAA29188@bilver.magicnet.net> <360938BE.3569E424@eaznet.com> <199809240148.VAA29188@bilver.magicnet.net> <19980924150846.C24890@Alameda.net> <3.0.3.32.19980925121618.00714074@207.227.119.2>
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On Fri, Sep 25, 1998 at 12:16:18PM -0500, Jeffrey J. Mountin wrote: > At 03:08 PM 9/24/98 -0700, Ulf Zimmermann wrote: > >On Wed, Sep 23, 1998 at 09:48:10PM -0400, Bill Vermillion wrote: > >> Eddie Fry recently said: > >> > Randal, > >> > > >> > Ronald says he has 2 class C's so his mask should be 255.255.255.0. > >> > >> He says he has two class C's but he's using class A addressing. > >> > >> Shouldn't the netmask really be 254.0.0.0 ? That way it will > >> supernet the 10.1 and the 10.2 into two parallel blocks out of > >> address.. 10.1 thru 10.2. > > > >254 would give you a supernet which includes 10.0.0.0/8 and 11.0.0.0/8. > > > >> > >> I know you can't use the 1 bit mask in the subnetting a c because > >> it will give a network address and a mask with nothing in between. > >> > >> Will a 254.0.0.0 set it up so that 10.1.0.0 is the base and > >> 10.2.255.255 is the broadcast. > > > >To do that, the netmask would be 255.252.0.0, but that would include > >10.0.0.0/16, 10.1.0.0/16, 10.2.0.0/16 and 10.3.0.0/16, so the broadcast > >would be 10.3.255.255 > > But isn't 10.0.0.0/255.254.0.0 a valid netmask? It would give 10.0.0.0/16 and 10.1.0.0/16, which wouldn't work for the posted is doing ie routing between the 2 networks. > > It certainly isn't a CIDR mask, but should be valid for supernets. It is a valid netmask, but it wouldn't include 10.1.0.0/16 and 10.2.0.0/16 as he wrote. > > > Jeff Mountin - Unix Systems TCP/IP networking > jeff@mountin.net -- Regards, Ulf. --------------------------------------------------------------------- Ulf Zimmermann, 1525 Pacific Ave., Alameda, CA-94501, #: 510-769-2936 Alameda Networks, Inc. | http://www.Alameda.net | Fax#: 510-521-5073 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-isp" in the body of the message
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