In computer networking, the maximum transmission unit (MTU) of a layer of a communications protocol is the size (in bytes) of the largest protocol data unit that the layer can pass onwards. MTU parameters usually appear in association with a communications interface (NIC, serial port, etc.). …

To find the MTU for Windows 7, type the following command at a DOS prompt:

netsh interface ipv4 show subinterfaces

To change the MTU for an adapter use the following command example:

netsh interface ipv4 set subinterface “Local Area Connection” mtu=1458 store=persistent

The following table summarizes the default MTU sizes for different network media.

  Network             MTU (bytes)
   -------------------------------
   16 Mbps Token Ring        17914
   4 Mbps Token Ring          4464
   FDDI                       4352
   Ethernet                   1500
   IEEE 802.3/802.2           1492
   PPPoE (WAN Miniport)       1480
   X.25                        576