You can use either routing/forwarding or bridging for this problem, however, bridging is simpler in many ways. If you use bridging, there is are fewer impacts on the design of the rest of your network. If you use routing, then the router that connects the PC with two interfaces to the Internet needs to know about the network on the other side of the PC (in a small network this can be done by adding a static route). So, in this example: ----------- ----------- ----------- | Router/ | | PC | | PC | | Firewall|.1 Net A .10| with 2 |.10 Net B .11| with 1 | | to |----------------| NICs |------------------| NIC | | Internet| 192.168.1.0 ----------- 192.168.2.0 ----------- ----------- Each network is /24 (netmask of 255.255.255.0) So, for this to work you need to do several things, the simplest is that you need to assign each PC the appropriate addresses. Firewall router: Local network IP: 192.168.1.1 /24 Internet address is not given in this example, but is assumed to exist ;-) Deafult gateway points to Internet. Static route defining gateway to 192.168.2.0/24 via 192.168.1.10. Router PC: Net A NIC: 192.168.1.10 /24 Net B NIC: 192.168.2.10 /24 Default gateway: 192.168.1.1 Other PC: NIC: 192.168.2.11 /24 Default Gateway: 192.168.2.10 Once configured, you will also need to turn on IPv4 forwarding in the Linux box. The most universal way is to run this command: "echo 1 > /proc/sys/net/ipv4/ip_forward" Although most distributions have thier own method to configure IP forwarding that persists across reboots. I hope that helps. Brad On Tue, 3 Feb 2009, [windows-1257] Kārlis Repsons wrote: > On Tuesday 03 February 2009 19:49:22 you wrote: > > > -----Original Message----- > > > > > > On Tuesday 03 February 2009 19:21:05 Gilad Benjamini wrote: > > > > Your description is not very clear, but my guess is that you want to > > > > > > run a > > > > > > > bridge on this PC. "man brctl" is a good place to start. > > > > > > It is all very simple: think of one computer with two RJ45 inputs, one > > > connected to LAN, other to laptop, which needs access to LAN too. The > > > problem > > > is: I have only one cable to LAN and no extra switch. > > > > You say yourself that your problem is the lack of a switch; i.e. you want > > your Linux machine to serve as the switch; i.e. you need a Linux bridge > > Well, most likely you are right and I will spend some more (but maybe not as > much) time tomorrow to set up that bridge. I just want to know, if its > absolutely necessary and there is no way to do routing / forwarding? > -- > To unsubscribe from this list: send the line "unsubscribe netfilter" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- To unsubscribe from this list: send the line "unsubscribe netfilter" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
