North American Network Operators Group
Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical

Re: smurf's attack...

  • From: Michael K. Sanders
  • Date: Fri Sep 05 18:10:49 1997 
In message <[email protected]>, DAVE NORDLUND writes:
>> Likewise, not all broadcast adresses necessarily end with .255, 
>> so filtering .255 won't help anyway in the presence of something
>> like a /25 with a X.X.X.127 broadcast.
>
>Agreed but it is not easy for a hacker to determine CIDR masks.  It

I'm sorry, but that's naive.  Unless you've taken steps to prevent
it, or you're just lucky, it's trivial to find out a lot of
things. Your mail server, for example, has a mask of 0xFFFFFF00. 

Another network at ukans.edu apparently has a mask of 0xFFFFFC00, 
and another is 0xFFFFF800.

:: Mike ::