I just installed linux 9.0 with 2 nic cards on an IBM P3 with 256 ram. I'm trying to use this computer as the main internet connection and file server for all of my computers on my network. The 2 nic cards were sucessefully installed. eth0 is the connection to the internet. That works fine. The problem I'm running into is that, when I activate eth2, my internet connection on eth0, stop working. When I deactivate eth2, my internet connection works again. Is there a step I miss when I installed the 2 nic cards?

eth2.... ? so you have 3 inetwork cards ?

the order is eth0 eth1 eth2.

what are you using to activate / deactivate cards ?

attepmt to activate both cards and post he output from "dmesg | grep eth" and "/sbin/ifconfig"

also, "uname -r" the latest version of linux is 2.6.10, are you sure you dont mean suSE9 / redhat9 / Mandrake9 ?

I'm sorry. I'm using Redhat 9.0 also, I ment to say eth1......(eth0 and eth1). I'm using the network cofiguration program to activate and deactive the nic cards.

Ok...so what about

post he output from "dmesg | grep eth" and "/sbin/ifconfig"

when I try those commands, it shows that both cards are installed and running.

what makes you think they are not running fine then ???

When I activate the first nic (eth0) my internet connection works fine. When I activate the second nic (eth1), my internet connection stop working. I can ping both cards when they both are active but, my internet connection doesn't work. When I deactivate the second nic (eth1). My internet connection works fine. Refer to the original post.

Smells like a routing error to me.
activate both cards, then run route.
whats the output of the command "route" ?

the default gateway should mention the correct eth device.

descripbe your network structure... eth0 is your external insternet connection... Via what ? Hub / Switch / Router / Direct internet connection ????

whats eth1 connected to ???
does the network on eth1 have a DHCP server ?
are you activating the NIC's manually, or VIA DHCP, if manually, what ip address / netmask / gateways are you using ???

All i can guess is happening here, is a DHCP server on eth1 is setting your default gatewateway to an address on eth1. there can only be 1 default gateway, so after eth1 is activated, all attempts to connect to the outside worls are router through the wrong card.

i would be tempted to activate eth1 manually with ifconfig.

When I type the "route" command, it shows me the kernel ip routing table which reads:

Destination Gateway Genmask Flags Metric Ref Use Iface
xxx.xxx.xxx * 255..... U 0 0 0 eth0
192.168.0.1 * 255...... U 0 0 0 eth1
etc...........................


I have a small network at home that I want to runs off the same DSL DHCP internet connection. I have one compter with 2 nic cards installed. One nic cards is (eth0) has the internet connection. Eth1 is routed to a ethernet hub. All other computer are connected to the hub. As I stated earlier, I can get on the internet from eth0 but when I activate eth1 for some strange reason, I lose the connection.

What brand are the nics?
Are they same? Linux can sometimes have fits if they are the same model.
I assume you have not enable any iptables stuff to forward network from eth0 to eth1 yet? If so what are your iptables config.

Brian1
" Google the Linux way @ http://www.google.com/linux "

I have'nt set my forwarding tables yet because I want to make sure my internet connection work first.

so.. the routing table.....
is the default gateway present and correct ????

i asked for the information because i thought it mifght be where the problem was...
just posting "etc etc" dont help.