D-Link DIR-840 User Manual page 32

Section 3 - Setup
MTU:
Maximum Transmission Unit - you may need to change the
MTU for optimal performance with your specific ISP. 1492
is the default MTU.
MAC Address:
The default MAC address is set to the Internet port's physical
interface MAC address on the broadband router. It is not
recommended that you change the default MAC address
unless required by your ISP. You can use the Clone.Your.
PC's. MAC. Address button to replace the Internet port's
MAC address with the MAC address of your Ethernet card.
D-Link DIR-840 User Manual 28