Complex home network

Hi

I have 3 machines and 2 ISP's with 2 wifi routers and am unsure as to the
best way to connect them together.

I want 1 machine to connect to 1 ISP and the other 2 machines to connect to
the other ISP.

*** I need all machines to be networked together ***

I want to make sure there are no internet conflicts which is a problem I
have encountered, ie 1 machine can forget which ISP it is supposed to be
using when it can "see" two connections to the net.

To allow different configurations I have the following hardware available:

2 wifi routers, each with 4 LAN RJ45 connections.

6 network cards.

An 8 port switch, if necessary.

Can someone please advise me on the best set up? All 3 machines are running
XP Professional. The idea is that 1 machine can "use" the other 2 with
remote desktop connection, that all hard drives are available to all
machines, and that 2 ISPs mean that should one fail, the other is there as a
backup.

Regards
James

"James" <(E-Mail Removed)> wrote in message
news:liALf.35506$(E-Mail Removed)...
> I have 3 machines and 2 ISP's with 2 wifi routers and am unsure as to the
> best way to connect them together.
>
> I want 1 machine to connect to 1 ISP and the other 2 machines to connect
> to the other ISP.
[snip]
> Can someone please advise me on the best set up? All 3 machines are
> running XP Professional. The idea is that 1 machine can "use" the other 2
> with remote desktop connection, that all hard drives are available to all
> machines, and that 2 ISPs mean that should one fail, the other is there
> as a backup.

There are a few options, I'll describe what I think is the simplest. First,
some names:

R1 = router connected to ISP 1
R2 = router connected to ISP 2
PC1 = PC that you want to connect to ISP 1
PC2, PC3 = the PCs that you want to connect to ISP 2

The idea is to have all five of the above on the same network, but with PC1
configured to use R1 for Internet access while PC2 and PC3 are configured to
use R2.

It is slightly simpler if you disable the DHCP server on both routers. Give
them different LAN-side addresses in the same range, with the same subnet
mask. For example, R1 = 192.168.0.1 and R2 = 192.168.0.2, both with subnet
mask 255.255.255.0. You didn't mention use of wireless, but if you do use
it, it would be simplest to disable wireless functionality on one of the
routers (it doesn't matter which).

Once that is sorted, you need to configure the PC interfaces. As above, they
need unique addresses all in the same range and with the same subnet mask as
the routers. For example, PC1 = 192.168.0.3, PC2 = 192.168.0.4, PC3 =
192.168.0.5, all with subnet mask 255.255.255.0. On PC1, add R1 (eg
192.168.0.1) as the default gateway and DNS server; on PC2 and PC3, add R2
(eg 192.168.0.2) as the default gateway and DNS server.

Finally, connect the two routers together with a cross-over cable, and
connect the PCs to the routers. You can connect any PC to any router; with j
ust three PCs it shouldn't make any significant difference.

To change which Internet connection (ISP 1 or 2) is being used by a PC,
change the default gateway and DNS servers to the address of the relevant
router. You may be able to add R2 as a secondary DNS server for PC1, and R1
for PC2 and PC3, and either add additional routes or use a batch file to
change the routing table. This would automate or simplify changing over, but
I haven't experimented so I don't know exactly how Windows handles it.
Regardless of how it happens, any connections from a given PC through one
router will become useless if that PC is changed or changes to using the
other (any connections between PCs should be unaffected).

For remote desktop and file sharing, the fact you have two routers is
irrelevant. All that matters is that all three PCs are on the same network,
just like a more typical single-router setup.

Alex

> It is slightly simpler if you disable the DHCP server on both routers.
> Give
> them different LAN-side addresses in the same range, with the same subnet
> mask. For example, R1 = 192.168.0.1 and R2 = 192.168.0.2, both with subnet
> mask 255.255.255.0. You didn't mention use of wireless, but if you do use
> it, it would be simplest to disable wireless functionality on one of the
> routers (it doesn't matter which).
>
> Once that is sorted, you need to configure the PC interfaces. As above,
> they
> need unique addresses all in the same range and with the same subnet mask
> as
> the routers. For example, PC1 = 192.168.0.3, PC2 = 192.168.0.4, PC3 =
> 192.168.0.5, all with subnet mask 255.255.255.0. On PC1, add R1 (eg
> 192.168.0.1) as the default gateway and DNS server; on PC2 and PC3, add R2
> (eg 192.168.0.2) as the default gateway and DNS server.
>
> Finally, connect the two routers together with a cross-over cable, and
> connect the PCs to the routers. You can connect any PC to any router; with
> j
> ust three PCs it shouldn't make any significant difference.

It works like a dream. Thankyou very much for your advice!!!!

The cable between the routers is a patch, not x-over, so at least one of
them must be auto-sensing. Even easier!

As for the wireless, I've left both routers transmitting and my laptop can
connect to either of them...

>
> To change which Internet connection (ISP 1 or 2) is being used by a PC,
> change the default gateway and DNS servers to the address of the relevant
> router. You may be able to add R2 as a secondary DNS server for PC1, and
> R1
> for PC2 and PC3, and either add additional routes or use a batch file to
> change the routing table. This would automate or simplify changing over,
> but
> I haven't experimented so I don't know exactly how Windows handles it.

Windows XP has allowed me to put in both default gateways and set a priority
order to each. Also I can put in all 4 DNS servers too. Upon experimenting I
have discovered that if a machine is set to, say, R1 and I kill that
connection, the machine uses R2 automatically (due to 2 gateways being
entered) so there is truly a backup internet connection there if one of them
fails. Cool :-)

This is also true of the two wifi channels, eg if the laptop is connected to
R2 and it fails (I pull out the power cord), it still finds a connection on
R1.

> Regardless of how it happens, any connections from a given PC through one
> router will become useless if that PC is changed or changes to using the
> other (any connections between PCs should be unaffected).
>
> For remote desktop and file sharing, the fact you have two routers is
> irrelevant. All that matters is that all three PCs are on the same
> network,
> just like a more typical single-router setup.
>
> Alex
>

This is brilliant. I never imagined I could connect the two routers together
without problems but now I understand what is actually going on in terms of
gateways, etc, it makes total sense. Again, thankyou for your help.


Me one happy chappy - now I just have to make use of all this bandwidth and
processing power, but that's another story :-)