D-Link DIR-68 - Manual (Page 25)

5 D-Link DIR-68 User Manual
Section  - Configuration
Maximum Transmission Unit - you may need to change the MTU for optimal performance with your specific ISP. 1400 is the default
MTU.
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.
MTU:
MAC Address: