Why must you use aggressive mode when a local FortiGate IPsec gateway hosts multiple dialup tunnels?
A. The FortiGate is able to handle NATed connections only with aggressive mode.
B. FortiClient supports aggressive mode.
C. The remote peers are able to provide their peer IDs in the first message with aggressive mode.
D. Main mode does not support XAuth for user authentication.
C.
FortiGate Security 6.2 Study Guide p. 654
‘If the dialup server contains multiple dialup VPNs, select AGGRESSIVE as the MODE. The use of peer IDs is required.’