How to clamp the MTU on an ethernet interface

[James McDonald]

Hi All,

I have been having some weird issues since I went from a bridging dsl 
modem where the ppp0 was terminated on my linux box to a stand alone 
adsl modem.

Google maps is failing to download image tiles and my work outlook web 
access site is also failing to download properly.

I want to clamp the MTU on my ethernet interface to 1452 bytes. This is 
a standard option when running pppoeconf to set up a connection. But how 
does one make the change when it's a simple ethernet interface?