MTU Value Display

This tells you the current value of MaxMTU for the registry key displayed in the ComboBox.

MTU is Maximum Transmission Unit. Different data protocols have different package sizes that cannot be exceeded. Knowledge of the MTU is required by TCP so that the package sizes can be optimised to prevent fragmentation during transmission across the internet. The Windows 95 default is 1500 which is the Ethernet standard MTU. The internet "standard" for MTU is 576 but many ISPs use MTU's greater than this (my ISP uses 1500). However, if you are connecting to a site on the other side of the world (or country) then your data may have to go through a router which has an MTU of 576. This would cause delays and retransmissions in your requested data if your MTU was greater than 576.

Conversely, having your MTU set too low can reduce your overall throughput as you will have more header information to process and more modem acknowledgements to send to cater for the smaller packet size.

The minimum permitted value for MTU is 68.