Updating route MTU when interface changes

[Joe Holden]

Hi guys,

I noticed this some years ago but I just checked and its still there - 
when the mtu of an interface is changed, any routes (eg connected route) 
using that interface aren't updated until the interface is shut/unshut - 
is this by design or is it an oversight?  Having to down/up remote 
machine interfaces that are potentially forwarding traffic just to 
change the mtu seems silly.

Ta,
Joe