Routing

From LinuxIntro

1. lan nic linux -> eth0 -> ip 192.168.0.1

lan nic windows -> 192.168.0.2 subnet -> 255.255.255.0

default gw -> 192.168.0.1 dns nr 1 -> 192.168.0.1

2. nic to dsl modem -> eth1 -> ip 192.168.2.1

3. routing/forwarding (as root)

rcnamed start
echo 1 > /proc/sys/net/ipv4/ip_forward
iptables -t nat -A POSTROUTING -o ppp0 -s 192.168.0.0/16 -j MASQUERADE
iptables -A FORWARD -i ppp0 -d 192.168.0.0/24 -j ACCEPT
iptables -A FORWARD -o ppp0 -p TCP --tcp-flags SYN,RST SYN -j TCPMSS \\
  --clamp-mss-to-pmtu
iptables -t nat -A PREROUTING -i ppp0 -p TCP --dport 4662 -j DNAT \\
  --to-destination 192.168.0.2
iptables -t nat -A PREROUTING -i ppp0 -p UDP --dport 5662 -j DNAT \\ 
  --to-destination 192.168.0.2
iptables -t nat -A PREROUTING -i ppp0 -p TCP --dport 24500:24505 -j DNAT \\
  --to-destination 192.168.0.2

Now both computers (Linux and Windows) are online, emule can run on both (ports 4672, 4662 and 5662). For ICQ file transfer, the ports 24500:24505 are open.