Troubleshooting Tip: Passive FTP not functioning correctly with Azure FortiGate VM

VIP is already configured for the server with all ports open.

Packet capture example for the problem:

The solution to this is to delete the FTP session helper.

First, find the FTP session helper:

config system session-helper

show 

Note: Look for FTP port 21(by default it is 'edit 9').

Snippet:

    next

    edit 8

        set name rtsp

        set protocol 6

        set port 8554

    next

    edit 9

        set name ftp

        set protocol 6

        set port 21

    next

    edit 10

        set name mms

        set protocol 6

        set port 1863

    next

end

config system session-helper

show

delete 9

end

Then try the FTP connection.