MTU (Maximum Transfer Unit) of an interface specifies the maximum number of bytes (octets) of a protocol data unit (PDU) supported by the protocol. For example, in Ethernet v2, the MTU has been standardized to 1500 bytes. In case of Jumbo Ethernet Frames, usually MTU can be in the range from 1500 to 9000. Some hardwares support more than 9000 (upto 16Kilobytes). The maximum limit is set by the hardware vendors.


In Solaris, MTU of an interface can be changed (at least) in two ways. One is by using ifconfig as in other operating systems and the other is by using dladm (Data Link Administration command).

Similar to Linux, FreeBSD and other operating systems, MTU of an interface can be changed using ifconfig.
Usage:

ifconfig <interface> mtu <new_allowable_mtu>

Example:

ifconfig bge0 mtu 6000

In Solaris, it is also possible to change MTU of an interface using dladm command. For this, the interface should be in unplumbed state.
Usage:

dladm set-linkprop -p mtu=<new_allowable_mtu> <interface>

Example:

dladm set-linkprop -p mtu=2000 bge0

Note that the MTU changed using dladm command is persistent. For a temporary change in MTU, pass an extra -t as below:

dladm set-linkprop -t -p mtu=<new_allowable_mtu> <interface>