In Reply to Ahmed Abdelkhaleq:
would someone please explain to me, why did they say that main mode can support a peer with one dailup VPN and it cannot be used with peer with multiple dailup VPN
Main mode only exchanges the suggested ISAKMP policies in the initial packets. If there are two (or more) dial-up VPN configurations to choose from, having only the remote IP address and the suggested policies list is not enough to determine which of them to use.
Aggressive mode exchanges the suggested ISAKMP policies, key and peer ID all in one shot - so there is now enough information available for the responder to choose the correct VPN.
If you do configure multiple main mode dial-up VPNs, the FortiGate will just simply select the first dial-up VPN alphabetically, which may not be the one you want.
