Maximum Transmission Unit

The MTU is the maximum payload length for a particular transmission media. For example, the MTU for Ethernet is typically 1500 bytes. (The maximum packet length for Ethernet is typically 1518 bytes, but that includes 14 bytes of Ethernet header and 4 bytes of CRC, leaving 1500 bytes of payload.) If a host wishes to send packet larger than the MTU for a network, the packet must be broken up into chunks no larger than the MTU.

The smallest MTU between two hosts is known as the path MTU.

Common MTU Values

Setting MTU Values


To set MTU values, use the ifconfig command on many OSes.

The ifconfig command might also report the MTU along with other information about the interface.


Getting your MTU value can be done using trial and error using the ping command.

Setting your MTU value can be done using the registry. See KB article 158474 for more details.

See also RFC 1191 for a table of common MTUs.

MTU (last edited 2008-06-25 19:06:12 by GeraldCombs)