iptables in linux

[Roger]

On Sat, 2011-11-12 at 20:37 +0100, Heinz Diehl wrote:
> On 12.11.2011, Roger wrote: 
> 
> > Is there a way to limit:
> > -number of log in attempts to 2, 
> > -the duration of a log in attempt to 3 seconds or less
> > -the number of times a username can be tried, prefer it set at 2 and
> > then not again for 24 hours if it fails.
> [....]
> 
> Switch off login with password and root login, and only allow login
> with RSA key. After that, you can safely ignore the "white noise" :-)
> 
>   
 I read about this and am concerned that if my computer dies and I
replace mb or other components, the RSA key could be different and I
won't be able to log in with the previous RSA.
Not understanding the process made me a bit nervous.
Roger