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I want to set up a home network that involves the following 4 devices:

  • An ADSL modem for internet access
  • Computer 1 (running windows XP)
  • Computer 2 (running windows 7)
  • A network Harddisk (NAS)

The ADSL modem only supports a network up to 100 Mbit, but I want the computers and the NAS to communicate via a 1Gbit network. Additionally I do not want the NAS to be able to communicate with the internet (so it should not be visible from the internet and it should not be able to see the ADSL modem.). Neither computer should rely on the other one to be "on", so they should not act as bridges.

What would be the best way to set up this configuration? Do I need to buy a router or switch (or neither or both) to get this working? Are there any special things I need to be aware of?

Background: in my current situation "Computer 2" does not yet exist. Computer 1 has two network cards, one connected to the modem (network 192.168.0.*) at 100 Mbits, and another to the NAS (network 192.168.222.*) at 1 Gbits.

I am about to buy Computer 2, but wonder if having two network cards in it is the best way of getting my intended set-up working. And I wonder if having two computers on the same two networks is going to cause troubles, both electrically (as adding the second computer creates a loop), and as far as routing goes (how do I tell the computers to use the fast network if they want to talk to each other or to the NAS, and the slow network for internet access).

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Just purchase a router that has support for 10/100/1000 ports. Once you do that connect all your devices to the router. Setup the router to block incomming traffic outside your network to only go to your Windows 7 computer. Windows XP is not secure and should not be connected to the internet. – Ramhound Jun 28 '12 at 12:04
Windows XP is secure if the appropriate steps are taken. Anti-virus, firewalls etc. – VBwhatnow Jun 28 '12 at 12:11
up vote 3 down vote accepted

I would buy a gigabit switch and then connect that to your router.


You would then set the PC's ip addresses using DHCP or whatever you used before.

For the NAS you could give it a static IP but leave the default gateway blank so it cannot reach the outside. Or you could use DHCP and use the modems built in firewall to deny all outgoing and incoming requests to the NAS

Now you do not require separate network cards and there should be no trouble with loopbacks or anything like that.

Feel free to comment if you need me to clarify anything.

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Eh wait, did you just say that a "switch" can connect networks of different speeds? In that case you just taught me something I didn't know before, thanks :) (I thought that that functionality required a "router") – Luc C Jun 28 '12 at 16:04
Just be sure that switch can set port speeds individually. Modem--Switch 100mbps and NAS/PC1/PC2--Switch 1Gbps. Don't know if this is anymore problem with new devices... – Sampo Sarrala Jun 28 '12 at 16:04
I'm too young to have ever seen a switch that did not auto negotiate speeds by default, you'll be fine. – VBwhatnow Jun 28 '12 at 16:14
@LucC Mostly if there is speed indicator lights for all ports instead of one common indicator then it probably can set speed per port basis. – Sampo Sarrala Jun 28 '12 at 16:15
A router is for connecting different networks. In this setup everything behind your modem is your local area network. The modem is a router that connects your network to the internet, which is of course, another network. – VBwhatnow Jun 28 '12 at 16:16

I would purchase a router that will work with the ADSL modem and which provides the other features you need. I would look for a router with a built-in firewall and built-in gigabit Ethernet switch.

Here's a review of one example (with more capability than you need)

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It would seem you just need an ordinary SoHO router. You connect the Model to the router (or you buy one with a builtin modem), the router establishes the internet connection and all other devices are connected to the router. As long as there aren't any fancy services enabled on the router (such as UPNP) no machine is visible from the internet except the router. If you configure all machines by hand, just don't tell the NAS about the router. If you chose to assign IP-Adresses with DHCP, don't worry that the NAS can potentially access the internet.

From what you write, all further considerations are not worth the time you need to think about it.

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