Direct connection via multiple Ethernet adaptors

I have two PCs, both connected via an unmanaged 10/100 switch to the
flat's broadband router. I'd like to fit a Gigabit Ethernet adapter card
to both PCs and connect them directly with a cable, to do backups and
other fast operations just between the two of them. I'm running Windows
2000 on both machines.

I can't find information about doing something like this; I want to
keep access to the broadband connection for both machines while having
this fast direct connection running at the same time, with file shares.
Is it possible at all?

 

Why not simply replace your 10/100 switch with a 10/100/1000 switch?
Then you have the future option of adding NAS, Media server or other
computer to your LAN at Gb speeds - and you'll only need one LAN
interface and driver SW in your computers.

It would be possible to do what you want by allocating different IP
addresses to each interface. You'll also need to do the necessary
routing in the PC, because you would have two routes that can reach the
same destination - but that's all extra SW overhead for each computer...

 

Cost, basically. I've got a USB GigE adaptor kicking around (from a
failed experiment trying to get a wired Ethernet connection working on a
PDA), and a PCI GigE adaptor for the other machine would cost about 6-8
quid. Adding a GigE switch to the network would cost me at least 25 quid
for a no-name cheapo and 35-40 quid for something like a Netgear. What
I've got hooked up right now is working OK, I'd just like to add an
extra fast connection between these two machines as cheaply as possible.
The rest of the network is running OK at 100Mbps capability.

Chunks of the wiring in this place are Cat5, not Cat5e or Cat6, so a
flat-wide upgrade to usable GigE would require a rewire and I'm not
wanting to go down that route just yet. Any NAS would be done "locally",
in one room, and we don't have a TV set here to stream "media" to.
Streaming Radio 4 LW, well maybe but that doesn't really require GigE
bandwidth.

But that would be too easy.

That's what I'm not sure about, how to set up routing so that a given
fileshare will be allocated to the GigE link and not to the primary
10/100 connection that also carries the broadband and other things like
the printer share. I don't want to mess up my existing configuration
with random experimentation.

 

install the adaptors and use a 4 pair straight thru cable between
them.

give the new adaptors IP addresses on a different subnet.

if that is all you did then w2k will make its own mind about which way
to connect.

Then you can bias the choice depending on interface costs, where you
point the default route for internet etc.

if backup etc is all just file sharing then you need to set up in the
applications, but if not you can vary the bindings of protocols
against each adaptor - for example microsoft file sharing on the old
one but not on the new one to limit which way that protocol goes.

if your backup allows an IP address for the remote machine, then pick
the one on the interface / subnet you want.

 

There may be a neater solution, but here's a quick and dirty fix that
should work I think (I'd try it but I don't have any Windows machines
here):

Say the router is 192.168.0.1 netmask 255.255.255.0. Set the gigabit
NICs in the two machines to 192.168.1.1 and 192.168.2.1, both with
netmask 255.255.255.0 and run

route add -p 192.168.1.0 mask 255.255.255.0 192.168.1.1 if 192.168.2.1

on the machine whose address is 192.168.2.1

route add -p 192.168.2.0 mask 255.255.255.0 192.168.2.1 if 192.168.1.1

on the machine whose address is 192.168.1.1

What this does:

route add -p : set a persistent route to override the default gateway
(which is your router)

192.168.1/2.0 mask 255.255.255.0 : the network you're adding a route to
(the network that the other machine's gigabit card is on)

192.168.1/2.1 : the gateway to that network (actually the machine you
want to connect to, but that's OK because everything it receives will
be for itself, and it knows what to do with that)

if 192.168.1/2.1 : the interface to use to connect to that gateway
(forces each machine to use its gigabit card to connect to that network)

If there are firewalls running on the machines you may need to open them
up to the other networks.

 

I just managed to get hold of a couple of cheap Realtek 8169 GigE cards
to actually try this out.

That's what I've got set up now, connected to the existing 10/100
switch and both machines, IP addresses 192.168.0.2 and 192.168.0.143
mask 255.255.255.0. This is working perfectly well, with both machines
having access to the internet and file shares available over the 10/100
link in both directions.

For reasons of numbering consistency I've actually set them up as:

Main: IP 192.168.2.143 mask 255.255.255.0

Backup: IP 192.168.1.2 mask 255.255.255.0

I tried this:

route add -p 192.168.1.0 mask 255.255.255.0 192.168.1.2 if
192.168.2.143

on the main machine (192.168.2.143).

which, as I understand it should have set up a permanent route between
the 192.168.1.* subnet via the backup machine's interface (192.168.1.2)
to the main machine (192.168.2.143). I got back an error:

"The route addition failed: Either the interface index is wrong or the
gateway does not lie on the same network as the interface. Check the IP
Address Table for the machine."

When I look up the help for "route" under W2K (route /?) It says the
"if" parameter is an index, like 2 or 3 rather than a specific IP
address as in your example.

EXAMPLE:

route ADD 157.0.0.0 MASK 255.0.0.0 157.55.80.1 METRIC 3 IF 2

I'm not sure where I can find this interface index number via either
the DOS ipconfig command or the GUI network device configuration.

I've set up the interface cards, loaded MS Update drivers (they're both
Realtek 8169 cards), connected them directly with a Cat6 cable and I can
ping them both ways successfully from either machine.

Assuming I can get these persistent routes to work how do I then go on
to create specific file shares that will use these routes and not the
default 10/100 speed connections already in place?

 

Looks like this script from the W2k Resource Kit should do it:
http://www.wilsonmar.com/vbs/listadapters.vbs

I think you'll just need to address them by IP address rather than
machine name e.g. \\192.168.1.2\backups once they're set up, BICBW.