Fortigate behind ISP modem

[HamB]

Hi all :) We have a fortigate 60C box, we intend to create a site to site VPN between our site and one of our clients' site. this fortigate box is behind an ADSL modem, so it' s wan interface is configured with a private IP address. to create the tunnel, we need to forward the IPsec trafic from the modem to the fortigate, which ports do we have to forward? Thanks all

[n0one]

Hello, It would be best to place your ISP modem into ' bridge mode' That will allow the fgt to get the external IP

[HamB]

Is it possible to do it with just port forwarding? because I don' t think the modem I have supports bridging.