2 computers, 2 NICs each, 2 LANs

  • Thread starter Thread starter Fred Marshall
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Fred Marshall

What happens if you have 2 (or more) computers, with 2 NICs each and assign
different IP addresses/ranges to corresponding NICs? For example:

Computer 1:
NIC 1: 192.168.1.2 Netmask: 255.255.255.0
NIC 2: 192.168.100.2 Netmask: 255.255.255.0

Computer 2:
NIC 1:192.168.1.3 Netmask: 255.255.255.0
NIC 2:192.168.100.3 Netmask: 255.255.255.0

The computers would be connected by one or two routers. If two routers, one
for the 192.168.1.xxx NICs, and one for the 192.168.100.xxx NICs (would it
matter if 1 or 2?)
Or, would be connected by two crossover cables - one on 192.168.1.xxx NICs,
one on 192.168.100.xxx NICs.

Presumably the Workgroup is the same as there can only be one Workgroup
assigned to the computer, right?

What if using 2 router(s) and they both have a WAN / Internet connection?
Which router / address range will be providing internet access to each
computer? Will it be one or the other only or can it be both for possibly
higher bandwidth?

This isn't homework and it isn't a particular problem I'm trying to solve.
I'm wanting to learn about what happens in a situation like this - motivated
by a question I tried to answer recently.

Thanks,

Fred
 
What happens if you have 2 (or more) computers, with 2 NICs each and assign
different IP addresses/ranges to corresponding NICs? For example:

Computer 1:
NIC 1: 192.168.1.2 Netmask: 255.255.255.0
NIC 2: 192.168.100.2 Netmask: 255.255.255.0

Computer 2:
NIC 1:192.168.1.3 Netmask: 255.255.255.0
NIC 2:192.168.100.3 Netmask: 255.255.255.0

The computers would be connected by one or two routers. If two routers, one
for the 192.168.1.xxx NICs, and one for the 192.168.100.xxx NICs (would it
matter if 1 or 2?)
Or, would be connected by two crossover cables - one on 192.168.1.xxx NICs,
one on 192.168.100.xxx NICs.

Presumably the Workgroup is the same as there can only be one Workgroup
assigned to the computer, right?

What if using 2 router(s) and they both have a WAN / Internet connection?
Which router / address range will be providing internet access to each
computer? Will it be one or the other only or can it be both for possibly
higher bandwidth?

This isn't homework and it isn't a particular problem I'm trying to solve.
I'm wanting to learn about what happens in a situation like this - motivated
by a question I tried to answer recently.
Click to expand...


Firstly you are confusing Workgroup with TCP/IP. Workgroup is a
throwback to NetBios on Win 3.1. It has nothing to do with Internet
communication.

If you have in mind a rationale for the configurations you are
describing, then there is probably a better solution.
 
Firstly you are confusing Workgroup with TCP/IP. Workgroup is a
throwback to NetBios on Win 3.1. It has nothing to do with Internet
communication.

If you have in mind a rationale for the configurations you are
describing, then there is probably a better solution.
Click to expand...

John,

No, I'm not confusing Workgroups and TCP/IP. Whatever gave you that idea?
One is a Windows thing. The other isn't limited to just Windows -
obviously. I simply asked some questions. I've presumed that Windows only
supports one Workgroup because there appears to be but one setting per
computer - in that regard I only asked for confirmation.

Any answers?

Fred
 
Computer 1:
NIC 1: 192.168.1.2 Netmask: 255.255.255.0
NIC 2: 192.168.100.2 Netmask: 255.255.255.0

Computer 2:
NIC 1:192.168.1.3 Netmask: 255.255.255.0
NIC 2:192.168.100.3 Netmask: 255.255.255.0

[...]
What if using 2 router(s) and they both have a WAN / Internet
connection? Which router / address range will be providing
internet access to each computer? Will it be one or the other
only or can it be both for possibly higher bandwidth?
Click to expand...

I think you'd find that any traffic going to the 192.168.1.x subnet
will go out the 192.168.1.x NIC and traffic going to the 192.168.100.x
subnet will go out the 192.168.100.x NIC. Traffic going anywhere else
will go out the NIC where the "default gateway" is defined, as the
default gateway must be on one of these two subnets. If more than one
gateway is defined, the first one is usually used unless it is not
working.

HTH,
John
 
John,

No, I'm not confusing Workgroups and TCP/IP. Whatever gave you that idea?
One is a Windows thing. The other isn't limited to just Windows -
obviously. I simply asked some questions. I've presumed that Windows only
supports one Workgroup because there appears to be but one setting per
computer - in that regard I only asked for confirmation.

Any answers?
Click to expand...

If there are two workgroups on the same LAN, only one will show in NN,
but you can access both of them. Try net view
\\computername-on-other-workgroup.

Without a rationale I have no incentive to wrap my brain around your
puzzle.
 
John Wunderlich said:
Computer 1:
NIC 1: 192.168.1.2 Netmask: 255.255.255.0
NIC 2: 192.168.100.2 Netmask: 255.255.255.0

Computer 2:
NIC 1:192.168.1.3 Netmask: 255.255.255.0
NIC 2:192.168.100.3 Netmask: 255.255.255.0

[...]
What if using 2 router(s) and they both have a WAN / Internet
connection? Which router / address range will be providing
internet access to each computer? Will it be one or the other
only or can it be both for possibly higher bandwidth?
Click to expand...

I think you'd find that any traffic going to the 192.168.1.x subnet
will go out the 192.168.1.x NIC and traffic going to the 192.168.100.x
subnet will go out the 192.168.100.x NIC. Traffic going anywhere else
will go out the NIC where the "default gateway" is defined, as the
default gateway must be on one of these two subnets. If more than one
gateway is defined, the first one is usually used unless it is not
working.

HTH,
John
Click to expand...

John,

OK - thanks. That makes sense.
Now, if each NIC has its own default gateway then.... ?
For example, if it's set up like this:

Computer 1:
NIC 1: 192.168.1.2 Netmask: 255.255.255.0 Gateways: 192.168.1.1 /
192.168.100.1
NIC 2: 192.168.100.2 Netmask: 255.255.255.0 Gateways: 192.168.100.1 /
192.168.1.1

Computer 2:
NIC 1:192.168.1.3 Netmask: 255.255.255.0 Gateways: 192.168.1.1 /
192.168.100.1
NIC 2:192.168.100.3 Netmask: 255.255.255.0 Gateways: 192.168.100.1 /
192.168.1.1

....where the first gateway shown above is entered as the default for each
NIC. So, there are two default gateways for each computer.

Fred
 
Now, if each NIC has its own default gateway then.... ?
For example, if it's set up like this:

Computer 1:
NIC 1: 192.168.1.2 Netmask: 255.255.255.0 Gateways: 192.168.1.1 /
192.168.100.1
NIC 2: 192.168.100.2 Netmask: 255.255.255.0 Gateways:
192.168.100.1 / 192.168.1.1

Computer 2:
NIC 1:192.168.1.3 Netmask: 255.255.255.0 Gateways: 192.168.1.1 /
192.168.100.1
NIC 2:192.168.100.3 Netmask: 255.255.255.0 Gateways: 192.168.100.1
/ 192.168.1.1

...where the first gateway shown above is entered as the default
for each NIC. So, there are two default gateways for each
computer.
Click to expand...

One way to find out is to set this up. Then, open a command window
and enter the command:
route print
This will print out the routing tables. Start at the bottom and the
first line you come to going up with IP/0.0.0.0 NetMask/0.0.0.0 will be
the one that all the outside traffic will be directed through.

HTH,
John
 
OK - thanks John. That's very helpful!

Fred

John Wunderlich said:
One way to find out is to set this up. Then, open a command window
and enter the command:
route print
This will print out the routing tables. Start at the bottom and the
first line you come to going up with IP/0.0.0.0 NetMask/0.0.0.0 will be
the one that all the outside traffic will be directed through.

HTH,
John
Click to expand...
 
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