Re: [cobalt-users] host.deny block range of IP

[flash22@xxxxxxx]

On Fri, 16 Feb 2001, Gerald Waugh wrote:

>  <flash22@xxxxxxx>  wrote
> 
> > 2 out of 3 ?  
> > 
> > 203-202=1 ;)
> > 
> > you want 
> > 
> > 202.0.0.0/254.0.0.0
> > 
> > Fortunatly the starting address is even, you can of course split the
> > addresses up and make 2 entries when necessary....
>  
> but wouldn't that deny 201.0.0.0 addresses!
> 

201 = 11001001
254 = 11111110
and = 11001000

The test is that (address AND netmask) == address

since 11001000 != 11001001 , it fails and doesn't reject

but

202 = 11001010
254 = 11111110
and = 11001010  which is == so it rejects 

and at the top limit..

203 = 11001011
254 = 11111110
and = 11001010 == address (202) so is rejected

above limit

204 = 11001100
254 = 11111110
and = 11001100 not =  202 so not rejected

helps?