How to add a route with a 2.2.x kernel ?

> I've just upgraded my kernel to 2.2.1. Now I cannot
> add a route for the loopback interface:
>
> fire:~# route add -net 127.0.0.0 dev lo
> SIOCADDRT: Invalid argument
 
 The 2.2.x kernels require that you specify the netmask when you add a
 route... 2.0.x would use a default value if it was not explicitly given.
 Try replacing the above with:
 
      route add -net 127.0.0.0 netmask 255.0.0.0 dev lo