ipfw rules vs routes to localhost?

["." at babolo.ru]

> I'm considering:
> 
>   ipfw add N deny ip from a.b.c.d to any
> 
> vs.
> 
>   route add -host a.b.c.d localhost
> 
> I need to block traffic to a number of IP addresses.  I thought I'd use
> ipfw to avoid things like UDP DNS lookups that might come in ant take up
> resources while my system tried to respond, but it's been suggested on
> another list that setting routes to localhost will use less resources.
> Ideally, I'd like to be able to block a few tens of thousands of IPs.
> 
> What's the scoop?
ipfw with huge list works slow.
Dont try huge route tables.

use in kernel:
pseudo-device   disc            #Discard device (ds0, ds1, etc)

and
ifconfig ds0 inet 0.0.0.1/32 (or else)
route add -host a.b.c.d 0.0.0.1
instead of localhost