*BSD News Article 78443


Return to BSD News archive

Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.mira.net.au!vic.news.telstra.net!act.news.telstra.net!psgrain!iafrica.com!uct.ac.za!quagga.ru.ac.za!howland.erols.net!newsfeed.internetmci.com!hunter.premier.net!news1.erols.com!news
From: Ken Bigelow <kbigelow@www.play-hookey.com>
Newsgroups: comp.unix.bsd.freebsd.misc
Subject: Re: Dual Ethernet Cards
Date: Tue, 17 Sep 1996 19:36:05 +0000
Organization: Erol's Internet Services
Lines: 54
Message-ID: <323EFDA5.76D3@www.play-hookey.com>
References: <3238986E.446B@phoenix.net> <51e7kt$jh@anorak.coverform.lan> <323C7859.1CFB@phoenix.net>
Reply-To: kbigelow@www.play-hookey.com
NNTP-Posting-Host: kenjb05.play-hookey.com
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
X-Mailer: Mozilla 3.0 (Win16; U)

Geoff Mohler wrote:
> 
> Brian Somers wrote:
> 
> > : How can I have two cards, and two default gateways with
> > : FreeBSD 2.1.5.
> >
> > You can't.  The default gateway is the target for all packets that havn't
> > got a specific entry in your routing table.  It doesn't make sense to have
> > two defaults.  Have a look at the route man page - it's a bit cryptic
> > unless you already know what it says ......
> >
> > What specifically are you trying to achieve ?
> 
> I am hosting two very large ftp and www sites on once machine..a machine
> that has
> plenty of capacity for it.
> 
> But I want to multihome this machine and its services, across two
> physical
> ethernet cards, and two networks.  But I do not want to route between
> the two.
> 

This is a guess and perhaps a gamble, based on other posts in this
thread and a couple of posts in other threads.

I'm assuming one thing you didn't mention in your previous posts: that
this same host machine not only has two Ethernet cards but also provides
your connection to the Internet, via some sort of PPP link or similar.

If this is the case, then you normally would set GATEWAY to "YES" in
/etc/sysconfig and all interfaces would be connected. What I understand
you to want is that each subnet have Internet access but not access to
each other.

If the foregoing assumtions are correct, try this: declare both subnets
as being in the same domain, but without IP overlaps. For example, for a
full Class C subnet, assign x.y.z.0 through x.y.z.128 to one subnet, and
x.y.z.129 through x.y.z.255 to the other, but use a netmask of
255.255.255.0 for both sides, and declare it that way on the gateway
machine. As I understand the logical assumptions made within FreeBSD, it
would not forward packets from one side to the other, even with
GATEWAY="YES", because it would assume you inherently had a single Class
C network containing all packets, so forwarding would be expected to
cause unwanted duplicate packets.

If I've mistaken your intent, please ignore the above.  :-)
-- 
Ken

Are you interested in   |
byte-sized education    |   http://www.play-hookey.com
over the Internet?      |