ping

[Major.Mikey]

what reason can be given for this command not to work?

 # ping -f ###.###.###.### 

I get a flood of 'E'
Then I try it w/o the flood option

 # ping ###.###.###.### 

and it says:

 8 packets transmited, 0 received, 100% packet loss

I'm trying to gie someone trying to break into my system a denial of service.
How do I make it so  that this box doesn't respond to pings or so that it 
doesn't respond to anything? If I do that will dial-up not work?