From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?ISO-8859-1?Q?J=F6rg_Harmuth?= Subject: Re: Blocking a range of source IPs to a specific port Date: Tue, 02 Aug 2005 10:26:49 +0200 Message-ID: <42EF2E49.5030302@mnemon.de> References: <42EE63E6.6070801@blackicehosting.com> <42EE9539.4070800@gmx.co.uk> <42EE9CA0.5020805@blackicehosting.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <42EE9CA0.5020805@blackicehosting.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: netfilter-bounces@lists.netfilter.org Errors-To: netfilter-bounces@lists.netfilter.org Content-Type: text/plain; charset="us-ascii" To: netfilter@lists.netfilter.org James Harrison schrieb: > However i'm still completely confused on the whole 0/9 issue- what does > this specify? We're talking about the notation 172.128.0.0/9 or shorter 172.128/9 or similar. The part after the slash is the subnetmask (netmask). It is the number of binary 1s starting from the left. 9 means the same as 255.128.0.0. The first octett has all bits set to 1 => 255, the second only the first bit => 128 and all others are 0 => 0 ;) HTH, Joerg