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The IPTables/NetFilter application is considered to be the fourth generation of Linux packet filtering implementations. The first generation was Alan Cox's port of BSD UNIX's ipfw to Linux 1.1. Jos Vos and others extended this and added the ipfwadm user tool . . .
In a bid to fight the growing menace from computer and router-based denial of service (DoS) attacks, security firm have developed a technique to dam the DoS data flood at source. Using funding from the Defence Advanced Research Projects Agency . . .
There's no question that firewalls are a key weapon in the IT arsenal. From a business perspective, the case for purchasing the right firewall for the job at hand is simple: Downtime costs money. Lost data costs money. A hacked site . . .
A draft of the Guide to Firewall Selection and Policy Recommendations (.pdf format) is now available for public comment. This document is intended for technical managers in the firewall and network security areas, but it would also prove useful to those wishing to know more about firewall technology and recommended policies. . . .
Transparent proxying frees you from the hassle of setting up individual browsers to work with proxies. If you have a hundred, or a thousand, users on your network, it's a pain to set up each browser and to use proxies -- or to try to convince users to go into their preferences and type in these symbols they don't understand.. . .
With the numbers of hackers and viruses these days, everyone who has a computer that's connected to a network -- including the Internet -- should have a firewall or be running behind one. This is a Q&A sessions about firewalls with . . .
... the latest Linux kernel, version 2.4, offers a number of improvements over the 2.2 kernel that make Linux a viable alternative for corporate firewalls. Netfilter, Linux's in-kernel "packet mangling" infrastructure, and iptables, the administrative tool that manages it, represent a . . .
The 2.2 version of the Linux kernel used the ipchains application to control the firewall. For standard firewalling, ipchains is a decent solution. We still use it on some of our machines, and there is still a positive argument for 2.2 . . .
The FTP protocol has strange peculiarities that make working behind a firewall somewhat difficult if not quite impossible. This document explains the problem, and solutions for both client and server behind a gateway doing NAT. AFAIK, it's the first time a solution is proposed for the server. Details of this solution are given for OpenBSD.. . .
For those of you who have taken the plunge and upgraded from kernel 2.2.X (or even 2.0.X) to 2.4.X, congratulations. If, like a number of folks, you're running some form of firewall using either ipchains or ipfwadm, your scripts may work . . .
What is IPFilter? Very simply, a package for permitting (or passing) and denying IP packets based on a range of criteria. It can also provide Network Address Translation (NAT) services, if desired. The IPFilter web site has more details. . . .
Firewalls are the bestsellers of tech security, cheap, formulaic and popular. Like a good paperback, they offer a pleasant escape from reality. An entire generation of business executives has come of age trained on the notion that firewalls are the . . .
Hopefully, this article will help you understand the principle of building a custom firewall. The firwall used for this article is pretty good, and you can use it, since you can adjust it to your needs as it is well commented. It is ideal for your home network. Just copy it, chmod it and off you go.. . .
If you access the Net from home using a DSL or cable modem (CM) connection that is always on, you definitely need a firewall. Why? Well, most hacks on the Internet happen because of automated port scans: "robots" scanning the Internet . . .
A United States-based network security watchdog has warned of a security hole in firewall software that will give an attacker access to the system and could lead to a denial of service attack. An advisory from CERT overnight . . .
Small and medium-size companies last year spent more money on hardware-based firewall appliances than on software-based systems, helping WatchGuard Technologies Inc. remain in the No. 1 position in the most competitive segment of the firewall market, according to a new analyst . . .
Firewalls and intrusion detection systems need an extra layer of protection, according to a leading security vendor. Paul Lawrence, European technical director at Top Layer Networks, said it was crucial to build up a picture of the data traffic on . . .
First you need to know how the firewall treats packets leaving, entering, or passing through your computer. Basically there is a chain for each of these paths. Any packet entering your computer goes through the INPUT chain. Any packet that your . . .
I'm sure many of you have been wondering how to use iptables to set up a basic firewall. I was wondering the same thing for a long time until I recently figured it out. I'll try to explain the basics to at least get you started.. . .
... there are a number of issues considered all too rarely by firewall administrators. Most IP level firewalls have a number of options for handling a packet. The packet can typically be accepted, dropped, or sent through another set of rules for inspection (allowing you to break up your ruleset into more manageable pieces). . .
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