> Date:    Sat, 12 Jan 2002 02:46:24 -0800
> From:    [log in to unmask]
> Subject: Re: Alternate Network Settings
>
> On 12 Jan 2002, at 1:19, Nostradamus Systems wrote:
>
> > I have 8 PC's using Windows ME sharing a leased line for internet
> > access.
> >
> > I have three hubs - which are connected - one with a router for
> > the leased line and other kit, and the other two each have 4 PC's
> > and an ISDN Router.
> >
> > Each group of 4 PC's share an ISDN connection if the leased line
> > fails.
> >
> > The PC's  have a static IP address,  and in order to use one of
> > the ISDN routers, the DNS Server, Gateway and IP address must be
> > changed in the network settings.
> >
> > Is it possible to automate a process to change these settings,  or
> > two "switch" to another configuration?
> >
> > TIA
> >
> > Geoff Gant
>
>   There *are* packages which will let you select between several
> networking configurations.  Unfortunately, I think most of them let
> you make this choice only as part of the boot process, so a change
> still means a reboot....
>
>   The more usual "commercial grade" failover solution is for an ISDN
> link to parallel the leased line, connecting to a second outside
> interface on the same router as the leased line -- running OSPF if it
> connects to the same router at the ISP's end as the leased line, and
> BGP if it connects to a different router or different ISP.  So the
> switchover occurs automatically in a few routing tables, without any
> IP address or gateway changes.
>
> 1.  You generally shouldn't have to change DNS server addresses.  Is
> there some reason you think you need to?
>
No - only that I thought it was necessary when splitting the "leased
network" in two.

> 2.  Putting the alternative connections on the other side of a router
> from the workstations, with NAT done at the router, should mean you
> never have to change a workstation IP address.
>
> 3.  In a case where the actual gateway changes, rather than update
> the gateway setting on each workstation, I point them all at a router
> which may not really be a gateway itself at all, but "knows" -- via
> OSPF or some other means -- about what gateways should currently be
> used.
What is OSPF please?

Is it feasible to:-
Set the ISDN routers within the address range 10.0.0.xxx
Add them to the list of Gateways on each PC.
Mix  addresses 158.152.xxx.xxx (leased line router) and 10.0.0.x (ISDN)
within the DNS - Server search Order.

If the leased line  goes down then would the switch to ISDN be automatic,
or would  a reboot be necessary to establish a working connection?

TIA - Geoff Gant
>
>   It should be possibke to get the effect you need without making
> these changes on every workstation.
>
> David Gillett

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