I assume Internet is connected on eth0 and your internet network on eth1

Install dhcp3-server. Make it listen on eth1. Edit /etc/dhcp3/dhcpd.conf:

# The ddns-updates-style parameter controls whether or not the server will

# attempt to do a DNS update when a lease is confirmed. We default to the

# behavior of the version 2 packages ('none', since DHCP v2 didn't

# have support for DDNS.)

ddns-update-style none;

Filling in the DNS manually seems the only way it works. Ripped out /etc/resolv.conf of the gateway.

# option definitions common to all supported networks...

option domain-name "pp.htv.fi";

option domain-name-servers 213.243.153.171, 213.243.153.172;


default-lease-time 600;

max-lease-time 7200;


# If this DHCP server is the official DHCP server for the local

# network, the authoritative directive should be uncommented.

authoritative;

# Use this to send dhcp log messages to a different log file (you also

# have to hack syslog.conf to complete the redirection).

log-facility local7;


subnet 192.168.0.0 netmask 255.255.255.0 {

option routers 192.168.0.1;

range 192.168.0.10 192.168.0.20;

}

And finally iptables:

iptables -t nat -F

iptables -t nat -A POSTROUTING -o eth0 -s 192.168.0.0/24 -j MASQUERADE