iptables openvpn and port forwarding

[deathraccoon]

I use Plex Media Server. I forward that port, in my case 32401, so I can access this service remotely. however, I also use a VPN service from time to time. my problem is that I need access to certain forwarded ports (32401, 21, 22) when the vpn is up, however since that gateway is that of the vpn, server, I can not configure it.

there are two ways of going about this as I see:

1) when the vpn is running, use iptables to route traffic destined for the above ports away from tun0 and into eth0 instead.

2) use iptables to run one port (transmission at 54089) over tun0 and expose eth0 to the rest of the web; I really only use the vpn for torrents so either solution would work.

my deficit is in skill with iptables. any suggestions? thanks.