Hi,
my question:

I have a vpn between a draytek 2830 (routerA, lan 192.168.10.1/24) and a draytek 2920 firmw 3.6.4 (routerB, lan 192.168.20.1/24)
My need is to forward a packet sent to the active wan of router A (example port 25) to an ip of router B lan (ex: 192.168.20.7)
tipically in lanB (192.168.20.7) there is a mailserver but port 25 on wan routerB is blocked.

I need to call port 25 on the wan of router A and forward it to mailserver, over vpn to ip 192.168.20.7

Thanks for any hint...

Conzi

Never tried that. I would assume you have set up a LAN<->LAN VPN already, then a Port forward?