Vsftpd FTP Server With Virtual Users ( Berkeley DB + PAM )

Posted on in Categories CentOS, FTP Server, Howto, Linux, Networking, package management, RedHat/Fedora Linux, Security last updated January 21, 2009

VSFTPD supports virtual users with PAM (pluggable authentication modules). A virtual user is a user login which does not exist as a real login on the system in /etc/passwd and /etc/shadow file. Virtual users can therefore be more secure than real users, because a compromised account can only use the FTP server but cannot login to system to use other services such as ssh or smtp.

Red Hat / CentOS Apache 2 FastCGI PHP Configuration

Posted on in Categories Apache, CentOS, Howto, Networking, package management, php, RedHat/Fedora Linux, Security, Tips last updated December 30, 2008

FastCGI is a protocol for interfacing interactive programs with a web server. FastCGI’s main aim is to reduce the overhead associated with interfacing the web server and CGI programs, allowing a server to handle more web page requests at once.

Also, PHP is not recommended with multithreaded Apache2 (worker MPM) because of performance and some 3rd party PHP extensions are not not guaranteed thread-safe.

nginx and lighttpd has inbuilt support for FastCGI. For Apache web server you need to use either mod_fastcgi or mod_fcgid.

mod_fastcgi allows server and application processes to be restarted independently — an important consideration for busy web sites. It also facilitates per-application security policies — important for ISPs and web hosting companies.

In this quick tutorial, you will learn about Apache 2 + mod_fastcgi + PHP installation and configuration under Red Hat Enterprise Linux / CentOS Linux version 5.x+.

How To Convert From a VMware Image To Virtualbox Image

Posted on in Categories GNU/Open source, Hardware, Howto, Linux, Linux desktop, Linux distribution, Linux Virtualization, package management, Tips, vmware, Windows, windows vista last updated December 22, 2008

VirtualBox is a virtual emulator like VMWare workstation. It has many of the features VMWare has, as well as some of its own.

I really like new Opensource VirtualBox from Sun. It is light on resources. Here is a quick tip – you can convert a VMware virtual machine (image) to a VirtualBox machine (image) using qemu-img utility, without reinstalling the GUEST operating system

Red Hat / CentOS: Chroot Apache 2 Web Server

Posted on in Categories Apache, Linux distribution, package management, RedHat/Fedora Linux, Security last updated December 22, 2008

A chroot on Red Hat / CentOS / Fedora Linux operating changes the apparent disk root directory for the Apache process and its children. Once this is done attacker or other php / perl / python scripts cannot access or name files outside that directory. This is called a “chroot jail” for Apache. You should never ever run a web server without jail. There should be privilege separation between web server and rest of the system.

In this exclusive series, you will learn more about:

  • Securing an Apache 2 web server under Red Hat Enterprise Linux / CentOS Linux using mod_chroot
  • Virtual hosting configuration
  • Troubleshooting Chrooted Apache jail problem.

How to View Internet Explorer inside Firefox

Posted on in Categories Download of the day, Howto, Linux, Linux desktop, Mozilla, package management, Windows, windows vista last updated October 7, 2008

I’m a devoted Firefox user like most of you. However, at work I use Internet Explorer for couple of web applications that works only on IE. Wouldn’t it be nice to embed Internet Explorer inside Firefox as a tab to browse the websites that works only on IE? This is exactly what Firefox add-on IE Tab does as explained below.

This is a great tool for web developers, since you can easily see how your web page displayed in IE with just one click and then switch back to Firefox.

Red Hat / CentOS Linux 5.x: Perl Performance Bug Fix Available

Posted on in Categories CentOS, GNU/Open source, High performance computing, Linux, Linux distribution, package management, RedHat/Fedora Linux last updated September 21, 2008

Perl version supplied with RHEL has bug, which will result code running at least 100 times slower than expected speed. Now, Red Hat updated perl packages that fix a performance issue. Earlier only solution was installing your own perl under /usr/local or other location. This fix will now take care of performance penalty.