Hello,

This is my first post regarding troubleshooting Fortigate devices.

To troubleshoot the VPN configuration of a Fortigate we will use the following commands:

#diag debug enable
#diag debug console timestamp en #this command shows the time-stamp
#diag debug app ike -1  # used for v4.0MR1
#diag vpn ike log-filter dst-addr4 ; #used from v4.0MR2 to the latest version
#diag debug app ike -1

<IP_PEER> is the ip of the remote peer.

To disable the VPN logging we can use:
#diag debug disable
#diag debug console timestamp dis
#diag debug app ike 0

The following commands show the active VPN tunnels:
#diag vpn tunnel list
#diag vpn gw list