Firewall - Page 11 - Results from #200

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Mike Murray describes how he patched the 2.2 Linux kernel to run an ipchains packet filtering firewall when the machine is halted. "As systems administrators, it's often funny how new and interesting information ends up in our hands. Sometimes, it's through an intentional course of study; other times, it seems to arrive by accident. That's exactly how the concept of using a halted Linux computer as a firewall occurred to me. . . .

Anthony Pell
Feb 10, 2002

Inside the Linux Packet Filter

In Part I of this two-part series on the Linux Packet Filter, Gianluca describes a packet's journey through the kernel. Network geeks among you may remember my article, ``Linux Socket Filter: Sniffing Bytes over the Network'', in the June 2001 issue of LJ, regarding the use of the packet filter built inside the Linux kernel.. . .

Anthony Pell
Feb 07, 2002

Use Linux firewall to fend off hackers

A firewall is software that prevents the flow of Internet traffic. Businesses and large network administrators use firewalls to contain traffic and maintain security. Firewalls keep traffic out, or they keep it in. A simple firewall configuration for most home users would block all outside traffic not generated at the users' request.. . .

Anthony Pell
Jan 24, 2002

Building a Linux Firewall

The 2.4 Kernel of Linux has a great tool called netfilter, which is a framework for creating firewalls. Many new Linux distributions such as RedHat 7.1 come with basic firewall rulesets that allow you to automatically create low, medium, or high . . .

Anthony Pell
Jan 03, 2002

HOWTO: Make a Firewall Sandwich (Funny)

There's a nice recipe for making a tasty, high-performance security checkpoint to replace a bland, low-performing single point of failure at the border between your network and the Internet.

Anthony Pell
Jan 02, 2002

Application Gateways and Stateful Inspection: Comparing and Contrasting

This article dated back in 1998 is one of the most informative articles I've seen on Application Gateways and Stateful Inspection. The Internet Security industry has grown tremendously in the past several years: the increase in demand for related products has . . .

Anthony Pell
Dec 18, 2001

PCX IP Tables Firewall

PCX Firewall is a perl script which works with several configuration files to generate 3 shell scripts (startfw, stopfw, and restartfw) which actually do the real work of the firewall. The design goal was to develop a complete IPTables based . . .

Anthony Pell
Nov 20, 2001

IPTables/NetFilter - Linux's Next-Generation Stateful Packet Filter

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 . . .

Anthony Pell
Nov 08, 2001

Reverse firewall dams DoS flood

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 . . .

Anthony Pell
Nov 07, 2001

Defense Mechanisms

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 . . .

Anthony Pell
Nov 05, 2001

Guide to Firewall Selection and Policy Recommendations

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. . . .

Anthony Pell
Oct 31, 2001

Transparent Proxying with Squid

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.. . .

Anthony Pell
Oct 29, 2001

Firewalls not perfect but needed these days

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 . . .

Anthony Pell
Oct 21, 2001

Netfilter and iptables: Stateful firewalling for Linux

... 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 . . .

Anthony Pell
Oct 12, 2001

10 minutes to an iptables-based Linux firewall

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 . . .

Anthony Pell
Sep 21, 2001

FTP and NAT: solutions

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.. . .

Anthony Pell
Sep 04, 2001

Taming the Wild Netfilter

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 . . .

Anthony Pell
Aug 26, 2001

IPFilter on OpenBSD

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. . . .

Anthony Pell
Aug 08, 2001

The Firewall Fetish

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 . . .

Anthony Pell
Jul 30, 2001

Commenting a firewall

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.. . .

Anthony Pell
Jul 28, 2001

Firewall - Page 11

An Introduction to UFW, Ubuntu’s ‘Uncomplicated’ Firewall

The Open Source Firewall – IPFire 2.27 – Core Update 173 Released: What’s New?

IPFire Hardened Linux Firewall Distro Is Now Powered by Linux Kernel 6.1 LTS