Change the MTU of network interface in Debian
What is MTU?
Maximum Transmission Unit, the largest physical packet size, measured in bytes, that a network can transmit. Any messages larger than the MTU are divided into smaller packets before being sent.
Default MTU Size for Different Network Topology
To change the MTU of an interface on GNU/Linux, you just need to tell ifconfig to do so, like this for example:
/sbin/ifconfig eth0 mtu 1492
To change it permanently on Debian, put it in the /etc/network/interfaces .where almost all network parameters are found. To do this, just add a line mtu to the definition of your interface. Example:
iface eth0 inet static
There is an exception, though.
Warning: the following is mostly obsolete in Sid and Etch
It seems that the dhcp clients are not configured by default to do the same for dynamically-assigned configurations . So, you need to use a tweak to achieve the same. We're going to use the pre-up feature of /etc/network/interfaces like this:
iface eth0 inet dhcp