How do I route inside my network?

[riclucx]

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I have a network and I divided in two by changing the subnet mask and using a linux box with 2 interface cards. One of these is connected to the hub where the gateway is connected. The other one is connected to my other computers, but I turned on the forwarding ( echo 1 > /proc/net/sys/ipv4/ip_forwarding ) and set up my interface cards, set the routing table correctly with ip, and in the side of my computers set the default gateway to the interface that is connected to the hub of my second network.
Forwarding does't happen. I'm doing this because I want to filter the traffic between the internet and my other computers, because they have real internet addresses. Please help!

[wassy121]

read up on iptables, this is the userspace program that interfaces with the kernel to make exactly what you are talking about happen.

[riclucx]

Yes, I know about iptables, and I know how to set up a firewall with it, the problem is that I want to use it as a filter between the internet and my network with real addreses, but my Linux box doesn't want to forward packets between them and I don't know why, because if I setup masquerading it works well.

[wassy121]

read more, iptables does more than just firewall. You can use it to do what you are talking about with the FORWARD chain. Yes, I did this exact thing at work about a year ago, but don't have access to those machines any more.

[Dolda2000]

This doesn't have to be configured with iptables. Just make sure that the FORWARD table ACCEPT as it's policy. Have you set the router up as the default gateway for all the machines on the network?

[riclucx]

thanks a lot. I solved the problem with your help.