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How To Implement SPF In Postfix
This tutorial shows how to implement SPF (Sender Policy Framework) in a Postfix 2.x installation. The Sender Policy Framework is an open standard specifying a technical method to prevent sender address forgery. There are lots of SPF extensions and patches available for Postfix, but most require that you recompile Postfix. Therefore we will install the postfix-policyd-spf-perl package from openspf.org which is a Perl package and can be implemented in existing Postfix installations (no Postfix compilation required).
Prevent Phishing with Mutual Authentication
Phishing is a man-in-the-middle attack. While many people think using time-bound, one-time passwords will solve the problem, they are wrong as attacks will just become automated. What is required is strong mutual authentication - authentication of the host to the user as well as the user to the host. This article demonstrates how to do that using open-source software from WiKID.
Fight Image Spam With FuzzyOCR And SpamAssassin On Debian/Ubuntu
This tutorial describes how to scan emails for image spam with FuzzyOCR. FuzzyOCR is a plugin for SpamAssassin which is aimed at unsolicited bulk mail containing images as the main content carrier. Using different methods, it analyzes the content and properties of images to distinguish between normal mails (ham) and spam mails. FuzzyOCR tries to keep the system load low by scanning only mails that have not already been categorized as spam by SpamAssassin, thus avoiding unnecessary work.
Install and Configure Auth Shadow on Debian/Ubuntu
Auth Shadow or mod-auth-shadow is a module for apache (and apache2, sort of) that enables authentication against /etc/shadow. The benefits being that any system user with a password can be authenticated for web_dav, subversion or simply an https server. The only other way to do this is with PAM. That method is dangerous because the apache user (www-data in my case) must be able to read /etc/shadow. Obviously, not a good idea. Auth Shadow accomplishes this safely by using a intermediate program called validate. This works because validate can be owned by root but executable by everyone. In the event that your server is compromised through apache, your password file will not be readable.
Virtual Users With Postfix, PostfixAdmin, Courier, Mailscanner, ClamAV On CentOS
In this how to I will explain how to setup a Postfix virtual mailserver with Courier-IMAP, Maildrop and Postfix Admin GUI. We will secure our mailserver with Mailscanner and Clamav as anti-virus and Spamassassin as anti-spam.
Secure your SSH deployment with WiKID two-factor authentication
In this document we are going to demonstrate how to combine two-factor authentication from WiKID with an SSH gateway server with hosted private keys to create a highly secure, auditable and easy to use remote access solution. The WiKID Strong Authentication System is a commercial/open source two-factor authentication solution.
How To Automatically Scan Uploaded Files For Viruses With php-clamavlib
This guide describes how you can automatically scan files uploaded by users through a web form on your server using PHP and ClamAV. That way you can make sure that your upload form will not be abused to distribute malware. To glue PHP and ClamAV, we install the package php5-clamavlib/php4-clamavlib which is rather undocumented at this time. That package is available for Debian Etch and Sid and also for Ubuntu Dapper Drake and Edgy Eft, so make sure you use one of these platforms.
How to configure OpenVPN to use WiKID Strong Authentication
The WiKID Strong Authentication System is a commercial/open source two-factor authentication solution. This guide demonstrates how to OpenVPN and SSH to use one-time passwords from WiKID. While both solutions support private key authentication, that may not be sufficient for your requirements; you may need one-time passwords for webmail or extranet access; or centralized authentication management and logging.
Securing the connection between MySQL and MySQL Administrator using an SSH tunnel
This is a description of how to set up a secure tunnel between your MySQL Server and a locally running MySQL Administrator using Putty. By creating a secure tunnel to your MySQL server using Putty, you can grant localhost access to powerful applications like MySQL Administrator while at the same time, make your server appear as if it isn't even there. In effect, make your MySQL server disappear from the outside world.
Key-Based SSH Logins With PuTTY
This guide describes how to generate and use a private/public key pair to log in to a remote system with SSH using PuTTY. PuTTY is an SSH client that is available for Windows and Linux (although it is more common on Windows systems). Using key-based SSH logins, you can disable the normal username/password login procedure which means that only people with a valid private/public key pair can log in. That way, there is no way for brute-force attacks to be successful, so your system is more secure.