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Re: Reflexive firewalls?
From: "0x90" <secbasics () spam gagspace com>
Date: Thu, 27 Dec 2007 19:28:35 +0100
My suggestion is google://iptables+recent+example
This is not perfect, it might not even be working, but your solution with nf
would probably look something like this:
$IPTABLES -A INPUT -p TCP --dport 1234 \
-m recent --name knock --set -j ACCEPT
$IPTABLES -A INPUT -p TCP --dport 22 -m recent \
--name knock --rcheck --seconds 120 --hitcount 1 -j ACCEPT
----- Original Message -----
From: "Danilo Chilene" <dchilene () impsat com>
To: "Ong Chin Kiat" <ong.chinkiat () gmail com>
Cc: <security-basics () securityfocus com>
Sent: Thursday, December 27, 2007 7:02 PM
Subject: Re: Reflexive firewalls?
I know how do this with PF.
Don't have any idea with iptables. :(
Ong Chin Kiat wrote:
I've recently used an SSH server that had an interesting
authentication mechanism. You first had to telnet to the machine on a
certain port. After doing this (it will just time out - no prompt),
you then SSH to the server in question. The telnet step has to be
carried out, if not SSH will just time out.
My question is, is this called reflexive firewalling, and can I
duplicate this with iptables?
Danilo F. Chilene
Global Crossing Limited
Tel.: (55 11) 3957-2945
Cel.: (55 11) 8231-1851
danilo.chilene () globalcrossing com