RE: Blocking sub-range of IP addresses
Hi
Consider each octet of an IP address in turn.
Octet:-
256-(2^n(4)).256-(2^n(3)).256-(2^n(2)).256-(2^n(1))
start with n(1), then n(2) and through to n(4).
where 0<=n(x)<=8
and x=1;x<=4;x++
and where x increments n(x-1)==8 always.
and to get the prefix length /mm =32 - (sum n(x))
Alastair
-----Original Message-----
From: Bill [mailto:bill07@shaw.ca]
Sent: 11 March 2003 20:25
To: debian-security@lists.debian.org
Subject: Blocking sub-range of IP addresses
Hello Debian,
I want to block all ip's ending in 224 to 255 but not 220 and others
searching the net I found I need to add "/27" to end of the ip.
I understand /8 /16 /24 /32 somewhat but...
My question: what makes /27 significant
X.Y.Z.224 - X.Y.Z.255
deny from 63.148.99.224/27
Thanks
P.s. for example, how would I block only X.Y.Z.23 - X.Y.Z.55 ???
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