The Penguinlinux.com Blog

Open relays allow people to use your mail server to deliver spam and mail to people whilst using your resources.
Continua”Is your mail server an open relay?”

There are many legitimate reasons for a Debian GNU/Linux user to wish to run Microsoft Windows applications. One approach involves using the wine program to run a single Windows executable in a fake Windows environment. An alternative is to run an entire Windows operating system within a Debian host. Qemu is a procesor emulator and virtualization program which allows you to do just that.
Continua”Running Microsoft Windows inside Debian: qemu”

There are many situations where you might want to send traffic over a secure link, and this is exactly what SSH allows you to do. Any form of TCP/IP connection can be sent across a tunnel providing you have access to a remote SSH server at the ‘far side’.
Continua”Tunneling connections securely with SSH”

Despite lacking a lot of features MySQL is one of the most popular database servers available for GNU/Linux platforms. Part of the attraction is that it’s much simpler to setup for a shared hosting system. This small HOWTO shows how to add new users to a MySQL system and keep their databases seperate from each other.
Continua”Adding new users to MySQL Databases”

If you’re running a webserver which gets cracked due to an insecure CGI, or PHP, script you’ll likely want to know what the attacker did. One simple way of doing that is to log all the commands which are executed on a machine.
Continua”Monitoring user activity, via snoopy”

If you run a webserver for lots of different users it can be useful to allow all the PHP scripts to run under the identity of the user who owns them - rather than having all PHP scripts upon the system run as the same user (Typically www-data on Debian systems). suphp allows you to do this easily.
Continua”Running PHP scripts as specific users with suphp”

When you run a largely dynamic website there’s a fair amount of effort which needs to be expanded for each visitor. For example pulling out headlines and article bodies from a database. Given that most users will not login and customize their screens you can imagine that a lot of the time you’re serving new visitors you’re actually serving identical content.
Continua”Speeding up dynamic websites with caching”

GNU Screen is an often overlooked application which allows you to run programs in a console section, detach from them and then later resume them. They even keep running when you logout.
Continua”Using GNU Screen”

mod-security is a simple intrusion detector and preventor for Apache, allowing you to wrap an additional layer of protection around your webserver.

mod-security is a rule-based IDS (intrusion protection system) which allows you to create rules describing abnormal requests to your webserver. When malucious requests are made which match your rules the request can be denied, and the details logged.
Continua”Intrustion detection and prevention for Apache with mod-security”

Thanks to the existance of the user-mode-linux project it is possible to run a complete copy of the GNU/Linux operating system on top of your existing system. These virtual servers are ideal for testing software installations, or setting up mass hosting for customers.
Continua”Running Linux on Linux - Virtual Servers”