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I have one intranet 192.168.0.x/ and I want to configure another intranet (192.168.1.x) under the first intranet(192.168.0.x).

(x.x.x.x)modem(192.168.0.x) > computers and one switch to > ( > computers.

I have some questions:

  1. the UDP used with Ubuntu need to be both crossover?

  2. the eth0 and eth1 configuration (file interface)?

  3. do I need another configuration in anothe file?

I am newbie, please help!!!

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You also have to ask yourself those questions : - Are those networks going to be reachable from outside ? - Is the modem/internet connection going to simply be shared between the computers ? - Is one network going to be able to reach the other network ? Like, 192.168.1.x computers will be able to reach 192.168.0.x computers, but do you want 192.168.0.x computers to reach 192.168.1.x ? If so, there has to be one more entry in the routing table of those computers.

You could actually replace the UBUNTU box between 192.168.0.x and 192.168.1.x with a cheap wired network router. No need to have wireless there. If you don't want 192.168.0.x to access 192.168.1.x, just connect this router with its WAN connection to the 192.168.0.x network, and configure it so that ITS internal network is 192.168.1.x, connect your 192.168.1.x computers to it and you're done.

Another solution could be in a "more intelligent" router, that could run DD-WRT. This replacement of the firmware will allow multiple segments, both sharing the internet connection, and you then can also establish supplemental routes so that one segment can reach the other segment.

Check on the net for DD-WRT (google), and then check there for supporting your existing router. If it is not supported, it is worth getting the right one from your local store. I use a Netgear one, and it works perfectly for me.

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Some good firewall software should do what you want. I am partial to Shorewall which is well documented and already packaged for Ubuntu. The documentation discusses various configurations, including the one you are considering.

It appears you want a variation on the two interface design. As I understand it you a configuration like this:

Internet  --+
            |-- Switch + Computers  (
Ubuntu    --+ 
=======   --+
            |-- Switch + Computers  (

This is a fairly standard configuration. You may need to masquerade the new network if you want to enable access to the Internet.

Alternatively, you could use a router running DDWrt or OpenWRT to handle both networks. Shorewall-lite will run on OpenWRT and would be modeled on a three-interface (Internet, DMZ, LAN) configuration.

Internet  --  Router  --+-- DMZ (
                        +-- LAN (
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