Re: Running seperate eth0 & ppp0 networks
Lee Bradshaw wrote:
>
> On Wed, Dec 16, 1998 at 10:19:35AM -0800, Ian Eure wrote:
> > Lee Bradshaw wrote:
> > >
> > > On Wed, Dec 16, 1998 at 03:29:04AM -0600, John C. Ellingboe wrote:
> > > > Lee Bradshaw wrote:
> > > > >
> > > > > On Mon, Dec 14, 1998 at 03:29:49PM +0000, Ian Stuart wrote:
> > > > > >
> > > > > > what I wish to do is set up my PPP connection so that (when it is up) all
> > > > > > requests for the ISPs network is routed via ppp0, whilst all other traffic
> > > > > > is routed via eth0
> > > > > >
> > > > > > (Assume that my academic lan is the class B 129.1 and my ISP is the class
> > > > > > B 130.2)
> > > > >
> > > > > Try something like:
> > > > >
> > > > > route add -net 130.2.0.0 dev ppp0
> > > > >
> > > >
> > > > This will limit your access to just the 130.2.0.0 network over ppp.
> > >
> > > That's what he wanted -- isp network over ppp0, everything else over eth0.
> > > I suspect your ppp0/eth0 setup is more common, but it's now what he needed.
> > >
> > > > Do
> > > >
> > > > route add -net [your local net address] dev eth0
> > > >
> > > > and use the "default route" option for ppp to get to everything on the
> > > > internet. I ran this way for some time and it worked fine for access
> > > > to either route.
> > Ah.... but, let's say that you also have file sharing or some other
> > service on your system, and that it is visible to the outside world
> > through your ethernet. Will the services still work, or will the system
> > send out the syn/ack packet (in reply to the syn for requesting a
> > connection) on the ethernet, or over the ppp?
>
> I'm not sure I understand the question. Addresses in the 130.2.0.0 net
> are routed through the ppp0 interface. Everything else is routed through
> eth0.
>
> In general requests from the eth0 interface will be serviced through
> eth0 and those from ppp0 will be serviced through ppp0. There are two
> wierd cases. 132.2.x.x addresses requesting services through eth0 - the
> reply will go through ppp0. Non 132.2.x.x addresses requesting services
> through ppp0 - the reply will go through eth0.
>
> If you have a specific problem in mind, please provide an example using
> the original ip addresses - 132.2.0.0 (isp) ppp0, 129.1.0.0 (local)
> eth0, default eth0.
Ok. Let's say I have a linux box on an ethernet. It's ip is
192.168.111.55. The router on the ethernet is 192.168.111.1. Let's say I
have a web server on 192.168.111.55, accessible from outside my local
network. Let's further say that I set up ppp the way you described, with
a network route to my localnet (route add -net 192.168.111.0 netmask
255.255.255.0 dev eth0) and the default set to the ppp0 interface (route
add default gw ip.addyof.ppp.peer dev ppp0). What happens when a request
for a web page comes in? Does the page get sent back from the ethernet
interface, with the ip 192.168.111.55, or through the ppp0 interface
with the dynamic address of the dialup?
--
______________________________________________________________
| ian eure, network admin, freelance security consultant, and |
| manically depressed paranoid schizophrenic, at your service. |
; <ieure@minion.org> - http://minion.org ;
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