Canon iR3245 Network Manual page 40

If you want to manually set the communication mode and Ethernet type for
specifying a particular Ethernet type setting:
2
<Auto Detect>: [Off]
Select the appropriate items for <Communication Mode> and <Ethernet Type>, according to
the network environment you are using.
To connect with 1000Base-T, select [Full Duplex] for <Communication Mode>.
2-12 Interface Settings