Hi there!

I connect to the internet through eth1 (external)... and have another network card (eth0) that has a crossover cable to another linux machine.

This is what I am doing:

(first, host computer)

# /etc/rc.d/rc.inet1.conf
#
# This file contains the configuration settings for network interfaces.
# If USE_DHCP[interface] is set to "yes", this overrides any other settings.
# If you don't have an interface, leave the settings null ("").

# Config information for eth0:
IPADDR[0]="192.168.10.1"
NETMASK[0]=""
USE_DHCP[0]=""
DHCP_HOSTNAME[0]=""

# Config information for eth1:
IPADDR[1]=""
NETMASK[1]=""
USE_DHCP[1]="yes"
DHCP_HOSTNAME[1]=""

# Config information for eth2:
IPADDR[2]=""
NETMASK[2]=""
USE_DHCP[2]=""
DHCP_HOSTNAME[2]=""

# Config information for eth3:
IPADDR[3]=""
NETMASK[3]=""
USE_DHCP[3]=""
DHCP_HOSTNAME[3]=""

# Default gateway IP address:
GATEWAY=""

# Change this to "yes" for debugging output to stdout. Unfortunately,
# /sbin/hotplug seems to disable stdout so you'll only see debugging output
# when rc.inet1 is called directly.
DEBUG_ETH_UP="no"

-- itest.sh
#!/bin/bash
# just temporary
# Delete and flush. Default table is "filter". Others like "nat" must be explicitly stated.
/usr/sbin/iptables --flush
/usr/sbin/iptables --table nat --flush
/usr/sbin/iptables --delete-chain
/usr/sbin/iptables --table nat --delete-chain
/usr/sbin/iptables -F INPUT
/usr/sbin/iptables -F OUTPUT
/usr/sbin/iptables -F FORWARD
/usr/sbin/iptables -P INPUT ACCEPT
/usr/sbin/iptables -P FORWARD ACCEPT
/usr/sbin/iptables -P OUTPUT ACCEPT
# Allow established connections and programs that use loopback
/usr/sbin/iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
/usr/sbin/iptables -A INPUT -s 127.0.0.0/8 -d 127.0.0.0/8 -i lo -j ACCEPT
# Masking
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -j MASQUERADE -o eth1

(client)

# /etc/rc.d/rc.inet1.conf
#
# This file contains the configuration settings for network interfaces.
# If USE_DHCP[interface] is set to "yes", this overrides any other settings.
# If you don't have an interface, leave the settings null ("").

# Config information for eth0:
IPADDR[0]="192.168.10.2"
NETMASK[0]=""
USE_DHCP[0]=""
DHCP_HOSTNAME[0]=""

# Config information for eth1:
IPADDR[1]=""
NETMASK[1]=""
USE_DHCP[1]="yes"
DHCP_HOSTNAME[1]=""

# Config information for eth2:
IPADDR[2]=""
NETMASK[2]=""
USE_DHCP[2]=""
DHCP_HOSTNAME[2]=""

# Config information for eth3:
IPADDR[3]=""
NETMASK[3]=""
USE_DHCP[3]=""
DHCP_HOSTNAME[3]=""

# Default gateway IP address:
GATEWAY="192.168.10.1"

# Change this to "yes" for debugging output to stdout. Unfortunately,
# /sbin/hotplug seems to disable stdout so you'll only see debugging output
# when rc.inet1 is called directly.
DEBUG_ETH_UP="no"

I think I've missed something...

Where is the router-daemon ? (I assume you want connect via the crossover into host an then out through the external link into internet)

a route add command?

tried this on host: (then on client after doing research)

route add -net 192.168.10.0 netmask 255.255.255.0 gw 192.168.10.1 dev eth0

then route add default gw 192.168.10.1

they can ping eachother but that's it (I want them to share internet connection)