IP format in hosts.allow file 1

[m1bzm]

Hi all,

At the moment in my hosts.allow file (REDHAT 6.2) Im using straight forward direct addressing i.e.

in.ftpd 192.168.3. 192.168.2.5 etc...

by typing in the whole ip address some octets to represent wildcards.

Im not too familiar with the formal IP notation where an IP range can be described using the "/" character i.e.

192.168.1.0/24

My questions are firstly can someone breifly explain how this notation works and secondly can I use it in my hosts.allow file to save me typing loads of addresses?

Thanks to all in advance...
Darren

 

[jimbopalmer]

IP addressing is 32 bit (each 3 digit decimal number is a 8 bit binary number) the /24 indicates that the first 24 bits (3 decimal numbers) are important and the last 8 bits are not. so any of the addresses 192.168.1.1 to 192.168.1.254 'match' the address as given. I love everyone til they prove otherwise, sadly some prove otherwise SO quickly