Now I discovered a new problem. Before I wasn't considering important nor noticed but my friend have his Xbox and tried to connect on the Live service. He couldn't log on. I checked closely and notice that his Xbox wouldn't connected unless it gets a higher MTU value of 1465. I was suprised because normally it sets to 1500.

So I tried each interfaces (3) to see if one was defect but apparently it wasn't. I have also did the same on plugging it do my Linksys router which gave the normal value of 1500. I'm confused.

I tried to force the value inside the network/interfaces file but it didn't.

Does anyone have a suggestion?

Here at home, I have my Debian router with 3 different network cards. eth0 is connected to my ISP, eth1 (10.0.0.0/26) is connected to switch and eth2 (10.0.0.64/26) to another switch. DHCP is active on both interface and dedicates IP without problem. Clients in each segments can ping within only the same network. The router can both ping the 2 local networks and have access to the Internet. However, local clients have no outgoing traffic neither between the local network and the Internet.

Now I'm stuck. Configurating iptables to NAT with one interface was a piece of cake but with a new one, it jammed. So I left it empty.

Also took a look on the routing table and it looks fine.

Kernel IP routing table
 Destination     Gateway         Genmask         Flags Metric Ref    Use Iface
 10.0.0.0        0.0.0.0         255.255.255.192 U     0      0        0 eth1
 10.0.0.64       0.0.0.0         255.255.255.192 U     0      0        0 eth2
 74.56.59.0      0.0.0.0         255.255.255.0   U     0      0        0 eth0
 0.0.0.0         10.0.0.65       0.0.0.0         UG    0      0        0 eth2
 0.0.0.0         74.56.59.1      0.0.0.0         UG    0      0        0 eth0
 0.0.0.0         10.0.0.1        0.0.0.0         UG    0      0        0 eth1

Network interfaces configuration:

auto eth0
iface eth0 inet dhcp

auto eth1
iface eth1 inet static
        address 10.0.0.1
        gateway 10.0.0.1
        netmask 255.255.255.192
        network 10.0.0.0
        broadcast 10.0.0.63

auto eth2
iface eth2 inet static
        address 10.0.0.65
        gateway 10.0.0.65
        netmask 255.255.255.192
        network 10.0.0.64
        broadcast 10.0.0.127

I have no idea with rules that I should apply for iptables and what are the other things that I'm missing?