Canon EOS-1D X Mark III Advanced User's Manual page 599

4.
Configure the port number.
Normally, set [Port number setting] to 00021 (for FTP/FTPS) or
00022 (for SFTP).
Select [OK] to go to the next screen.
Go to step 6 if you selected [FTP] or [FTPS] in step 1. Go to step 5 if
you selected [SFTP].
5.
Configure the SSH login authentication settings.
Select [User name] and [Password] to access the virtual keyboard
( ) and enter the user name and password for SSH password
authentication.
Select [OK] to go to the next screen.
6.
Configure the passive mode setting.
Not displayed if you selected [SFTP] in step 1.
Select [OK] to go to the next screen.
If an Error 41 (Cannot connect to FTP server) is displayed in step 9,
setting [Passive mode] to [Enable] may resolve it.
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