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Search results for Firewalling with OpenBSD's PF packet filter

OpenBSD

Rebuilding the OpenBSD kernel

Post date: April 24, 2005, 20:04 Category: System Views: 4064 Comments
Tutorial quote: Users who want their OpenBSD machine to perform specific functions or need additional device drivers might want to customize their kernel. In other OS's, like some types of Linux, it is very popular to rebuild the kernel because the default is so bloated. For most users, the default OpenBSD kernel is sufficient; however, you should still apply kernel patches, which will require rebuilding and installing a fresh kernel.
Debian

How to filter spam with Spamassassin and Postfix in Debian

Post date: April 20, 2008, 18:04 Category: Network Views: 3433 Comments
Tutorial quote: We have already discussed how to install mail server with postfix+Devcot+SASL +Squirrel Mail in this article we will see how to add spam filter for postfix mail server.Apache SpamAssassin is an extensible email filter that is used to identify spam. Once identified, the mail can then be optionally tagged as spam for later filtering. It provides a command line tool to perform filtering, a client-server system to filter large volumes of mail, and Mail::SpamAssassin, a set of Perl modules allowing Apache
SpamAssassin to be used in a wide variety of email systems.

OpenBSD

OpenBSD 101 - Tutorial for Beginners

Post date: September 20, 2006, 20:09 Category: System Views: 10613 Comments
Tutorial quote: Some of the information in this tutorial can be found in the OpenBSD FAQ section. Though here the the FAQ has been trimmed down and presented in an easier to read format.
Unix+clones

Encrypted NFS with OpenSSH

Post date: May 21, 2005, 19:05 Category: Network Views: 2774 Comments
Tutorial quote: NFS is a widely deployed, mature, and understood protocol that allows computers to share files over a network. The main problems with NFS are that it relies on the inherently insecure UDP protocol, transactions are not encrypted, hosts and users cannot be easily authenticated, and its difficulty in firewalling. This article provides a solution to most of these problems for Linux clients and servers. These principles may also be applied to any UNIX server with ssh installed. This article assumes basic knowledge of NFS and firewalling for Linux.
SmoothWall

Install SquidGuard on Smoothwall

Post date: April 12, 2005, 18:04 Category: Software Views: 10734 Comments
Tutorial quote: squidGuard describes itself as: "An ultrafast and free filter, redirector and access controller for Squid". In my experience, it is the ideal web filter for use with Smoothwall and IpCop since it is lightweight and easy to set up. I use it on an i486, 33Mhz system with 18Mb of Ram and 500Mb of hard drive - and while there is a minor performance hit, the hit is not significant.

This simple how-to describes the steps I took to install squidGuard on my system - it should work for yours too.
OpenSUSE

IPTraf - Console based IP Traffic Monitor in openSUSE

Post date: March 3, 2009, 05:03 Category: Network Views: 6196 Comments
Tutorial quote: IPTraf is a console-based network statistics utility for Linux. It gathers a variety of figures such as TCP connection packet and byte counts, interface statistics and activity indicators, TCP/UDP traffic breakdowns, and LAN station packet and byte counts. IPTraf is an IP traffic monitor that shows information on the IP traffic passing over your network.
OpenBSD

Failover Firewalls with OpenBSD and CARP

Post date: April 28, 2005, 02:04 Category: Network Views: 7585 Comments
Tutorial quote: Firewalls are a required component in commercial and residential computer networks. For many installations, the firewall is a single point of failure between client systems and external resources. It can also become a liability when hardware or applications fail, leaving potential customers unable to reach your servers. A properly designed and executed failover configuration for your primary firewall will address many of these concerns. This article introduces a proven method for installing redundant stateful firewalls using native OpenBSD features.
Linux

Three tools to help you configure iptables

Post date: May 25, 2005, 14:05 Category: Network Views: 3062 Comments
Tutorial quote: Every user whose client connects to the Internet should configure his firewall immediately after installation. Some Linux distributions include firewall configuration as a part of installation, often offering a set of defaults configurations to choose from. However, to ensure that your machine presents the minimum "attack surface" (a measure of the number of vulnerable ports, user accounts, and sockets exposed to attack) to the predatory inhabitants of the Internet, you may need to do some manual configuration of your firewall. Here are three tools that can help.
The Linux kernel (version 2.4 onwards) contains a framework for packet filtering and firewalling using netfilter and iptables. Netfilter is a set of hooks inside the Linux kernel that allows kernel modules to register callback functions with the network stack. Iptables is a generic table structure for the definition of rulesets. Each rule within an IP table consists of a number of classifiers (iptables matches) and one connected action (iptables target). Iptables has extensive documentation that can be accessed online or by typing man iptables at the command line. Yet despite the depth of the documentation available for iptables, its complexity can be baffling.
Linux

Postfix with dkfilter (DomainKeys Implementation)

Post date: December 7, 2006, 21:12 Category: Security Views: 4014 Comments
Tutorial quote: DomainKeys is an anti-spam software application in development at Yahoo that uses a form of public key cryptography to authenticate the sender's domain. dkfilter is an SMTP-proxy designed for Postfix. It implements DomainKeys message signing and verification. It comprises two separate filters, an outbound filter for signing outgoing email on port 587, and an inbound filter for verifying signatures of incoming email on port 25. This document shows step-by-step how to install dkfilter for Postfix to deploy DomainKeys signing and verification.
Unix+clones

Using MySQL to benchmark OS performance

Post date: April 12, 2005, 07:04 Category: Benchmarks Views: 3462 Comments
Tutorial quote: It seems to be an exciting time for *nix operating systems, with a number of them recently releasing new versions that bring the addition of expanded features and claims of improved performance. If you're using GNU/Linux, OpenBSD, NetBSD, FreeBSD, or Solaris as a database server, you've probably recently considered an upgrade or switch to another OS in that list due to marketing hype and hearsay. This article will show you how to benchmark operating system performance using MySQL on these OSes so you can find out for yourself if you're missing out. While this may not necessarily be indicative of overall system performance or overall database application performance, it will tell you specifically how well MySQL performs on your platform.

The following operating systems were used for the comparison testing:
- FreeBSD 4.11
- FreeBSD 5.3
- NetBSD 2.0
- Linux 2.6
- Linux 2.4
- Solaris 10 x86 (build 69)
- OpenBSD 3.6
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