Canon EOS-1D X Instruction Manual page 29

Automatic Image Transfer After Each Shot
Enabling LAN Power Management
In the menu, select [Communication settings] [Network
settings] [Set up] [LAN power save].
When this option is set to [Enable], the camera will log off from the
FTP server after transfer and switch to standby mode. Wired
connectivity will be restored automatically when you attempt to
transfer images, and the camera will reconnect to the FTP server.
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