Rules for iptables. Two VPNs over One External IP [SOLVED]

Question

VPN

Need help writing rules for iptables (ubuntu 10.10).
Network structure:
Server - network eth1 192.168.0.1/24 and modem adsl ppp0 8.8.8.8 through it go to the Internet.

There are 2 PCs with addresses 192.168.0.2 and 192.168.0.3 on both networks. VPN is up.
The first PC 192.168.0.2 vnp connects to the Internet address 9.9.9.9 The
second PC 192.168.0.3 vnp connects to the Internet address 10.10.10.10

interface ppp0

Now it turns out that only one of the PCs can work, the second vnp is not tied.

TCPDUMP gives such information IP 192.168.0.3.500 > 10.10.10.10.500: isakmp: phase 1 I ident

and so it repeats

Answer 1

echo 1 > /proc/sys/net/ipv4/ip_forward # /etc/sysctl.conf
$IPT -v -t mangle -A PREROUTING -i eth1 -s 192.168.0.1 -j MARK --set-mark 10
$IPT - v -t mangle -A PREROUTING -i eth1 -s 192.168.0.2 -j MARK --set-mark 10
$IPT -v -t mangle -A PREROUTING -i eth1 -s 192.168.0.3 -j MARK --set-mark 10
$IPT -v -t nat -A POSTROUTING -o ppp0 -m mark --mark 10 -j SNAT --to-source=8.8.8.8
will route everything, add restrictions and forward ports to client ports if necessary. Not this way?

Answer 2

First of all, what immediately catches your eye is that 8.8.8.8 is Google's dns! So you already have some rules, would show then