The router is forwarding all traffic from an IP range, that goes towards outside the local network, to this host (that is intended to be a VPN concentrator). Using tcpdump on the host verifies this.
The host has an OpenVPN VPN tunnel established, named
tun0. We can access the Internet through it, so the default route is properly working.
Now, we've enabled both
sysctl, and added the corresponding
iptables rules to allow traffic to be forwarded and NAT'd:
iptables -A POSTROUTING -o tun0 -j MASQUERADE iptables -A FORWARD -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT iptables -A FORWARD -i eth0 -o tun0 -m conntrack --ctstate NEW -j ACCEPT
But traffic is still not being forwarded to
tun0 (as checked with
Any idea as to what could be going wrong, or what could we be missing?