Linux system administration and security

Information for Linux System Administration

Virtual hosting with vsftpd, MySQL on Debian

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Vsftpd is one of the most secure and fastest FTP servers for Linux. Usually vsftpd is configured to work with system users. This document describes how to install a vsftpd server that uses virtual users from a MySQL database instead of real system users. This is much more performant and allows to have thousands of ftp users on a single machine. read more...

permapage | score:9998 | -falko, March 10, 2010

Tutorial: Nginx WebServer Security

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Nginx is a lightweight, high performance web server/reverse proxy and e-mail (IMAP/POP3) proxy. It runs on UNIX, GNU/Linux, BSD variants, Mac OS X, Solaris, and Microsoft Windows. According to Netcraft, 6% of all domains on the Internet use nginx webserver. Nginx is one of a handful of servers written to address the C10K problem. Unlike traditional servers, Nginx doesn't rely on threads to handle requests. Instead it uses a much more scalable event-driven (asynchronous) architecture. Nginx powers several high traffic web sites, such as WordPress, Hulu, Github, and SourceForge. This page collects hints how to improve the security of nginx web servers running on Linux or UNIX like operating systems. read more...

mail this link | permapage | score:9981 | -nixcraft, March 9, 2010

Set up WebDAV and Lighttpd on Ubuntu 9.10

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This guide explains how to set up WebDAV with lighttpd on an Ubuntu 9.10 server. WebDAV stands for Web-based Distributed Authoring and Versioning and is a set of extensions to the HTTP protocol that allow users to directly edit files on the lighttpd server so that they do not need to be downloaded/uploaded via FTP. Of course, WebDAV can also be used to upload and download files. read more...

permapage | score:9981 | -falko, March 9, 2010

Fedora 12 GlusterFS Tutorial: Distributed storage on four nodes

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This tutorial shows how to combine four single storage servers (running Fedora 12) to one large storage server (distributed storage) with GlusterFS. The client system (Fedora 12 as well) will be able to access the storage as if it was a local filesystem. GlusterFS is a clustered file-system capable of scaling to several peta-bytes. It aggregates various storage bricks over Infiniband RDMA or TCP/IP interconnect into one large parallel network file system. Storage bricks can be made of any commodity hardware such as x86_64 servers with SATA-II RAID and Infiniband HBA. read more...

mail this link | permapage | score:9970 | -falko, March 7, 2010

Tutorial: Create an NFS-like storage server with GlusterFS on Fedora 12

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This tutorial shows how to set up a standalone storage server on Fedora 12. Instead of NFS, I will use GlusterFS here. The client system will be able to access the storage as if it was a local filesystem. GlusterFS is a clustered file-system capable of scaling to several peta-bytes. It aggregates various storage bricks over Infiniband RDMA or TCP/IP interconnect into one large parallel network file system. Storage bricks can be made of any commodity hardware such as x86_64 servers with SATA-II RAID and Infiniband HBA. read more...

mail this link | permapage | score:9967 | -falko, March 8, 2010

Linux: Utilizing a multicore CPU

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Almost all systems sold nowadays have at least a dual-core CPU, even triple- or quad-cores are getting cheaper and getting standard in the near future. But how to utilize your shiny x-core to it's full potential, with applications that are only utilizing one core? With Linux, which has strong multitasking capabilities as all unixoid operating systems, there is an easy possibility to parallelize tasks which are normally only using one core of an x-core CPU. read more...

permapage | score:9961 | -falko, March 3, 2010

Nmap tutorial

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An Nmap tutorial for the beginner...

What is Nmap? Short for "network mapper," nmap is a veritable toolshed of functionality to perform network scans. It can be used for security scans, simply to identify what services a host is running, to "fingerprint" the operating system and applications on a host, the type of firewall a host is using, or to do a quick inventory of a local network. It is, in short, a very good tool to know.

GlusterFS Tutorial: High-Availability storage on Fedora 12

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This tutorial shows how to set up a high-availability storage with two storage servers (Fedora 12) that use GlusterFS. Each storage server will be a mirror of the other storage server, and files will be replicated automatically across both storage servers. The client system (Fedora 12 as well) will be able to access the storage as if it was a local filesystem. GlusterFS is a clustered file-system capable of scaling to several peta-bytes. It aggregates various storage bricks over Infiniband RDMA or TCP/IP interconnect into one large parallel network file system. Storage bricks can be made of any commodity hardware such as x86_64 servers with SATA-II RAID and Infiniband HBA. read more...

mail this link | permapage | score:9937 | -falko, March 2, 2010

Tutorial: OpenSUSE 11.2 Samba server with tdbsam

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This tutorial explains the installation of a Samba fileserver on OpenSUSE 11.2 and how to configure it to share files over the SMB protocol as well as how to add users. Samba is configured as a standalone server, not as a domain controller. In the resulting setup, every user has his own home directory accessible via the SMB protocol and all users have a shared directory with read-/write access. read more...

permapage | score:9936 | -falko, January 13, 2010

Headless VirtualBox 3.1.x on Debian Linux

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This guide explains how you can run virtual machines with Sun xVM VirtualBox 3.1.x on a headless Debian Lenny server. Normally you use the VirtualBox GUI to manage your virtual machines, but a server does not have a desktop environment. Fortunately, VirtualBox comes with a tool called VBoxHeadless that allows you to connect to the virtual machines over a remote desktop connection, so there's no need for the VirtualBox GUI. read more...

permapage | score:9935 | -falko, February 23, 2010

Tutorial: Install Apache 2, PHP5, MySQL on Ubuntu 9.10

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LAMP is short for Linux, Apache, MySQL, PHP. This tutorial shows how you can install an Apache2 webserver on an Ubuntu 9.10 server with PHP5 support (mod_php) and MySQL support. read more...

permapage | score:9933 | -falko, November 27, 2009

Ksplice Uptrack tutorial: Ubuntu 9.10 no-reboot kernel upgrade

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Ksplice Uptrack is a subscription service that lets you apply 100% of the important kernel security updates released by your Linux vendor without rebooting. Ksplice Uptrack is freely available for the desktop versions of Ubuntu 9.10 Karmic and Ubuntu 9.04 Jaunty. This tutorial shows how to install and use it on an Ubuntu 9.10 desktop. read more...

permapage | score:9928 | -falko, February 24, 2010

Set up WebDAV with Lighttpd on OpenSUSE 11.2

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This guide explains how to set up WebDAV with lighttpd on an OpenSUSE 11.2 server. WebDAV stands for Web-based Distributed Authoring and Versioning and is a set of extensions to the HTTP protocol that allow users to directly edit files on the lighttpd server so that they do not need to be downloaded/uploaded via FTP. Of course, WebDAV can also be used to upload and download files. read more...

permapage | score:9926 | -falko, March 5, 2010

Tutorial: Install Lighttpd, PHP5, MySQL on OpenSUSE 11.2

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Lighttpd is a secure, fast, standards-compliant web server designed for speed-critical environments. This tutorial shows how you can install Lighttpd on an OpenSUSE 11.2 server with PHP5 support (through FastCGI) and MySQL support. read more...

permapage | score:9921 | -falko, February 22, 2010

Tutorial: Install Cherokee with PHP5, MySQL on Ubuntu 9.10

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Cherokee is a very fast, flexible and easy to configure Web Server. It supports the widespread technologies nowadays: FastCGI, SCGI, PHP, CGI, TLS and SSL encrypted connections, virtual hosts, authentication, on the fly encoding, load balancing, Apache compatible log files, and much more. This tutorial shows how you can install Cherokee on an Ubuntu 9.10 server with PHP5 support (through FastCGI) and MySQL support. read more...

permapage | score:9920 | -falko, February 17, 2010

Install and Configure OpenLDAP on Ubuntu 9.10

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The configuration of OpenLDAP got a bit (more) complicated. cn=config is still used, but when installing the packages from the repositories only a skeleton configuration of openldap is installed. You're not asked anymore to provide a password when the package is installed and issuing the "dpkg-reconfigure slapd" only resets openldap to the skeleton configuration. You will have to set up the openldap database, root dn and acl's yourself using the root account (or sudo) in order to configure openldap. Here is how I configured openldap in Karmic Koala, but I do not issue any guarantee that this setup will suit your needs or works for you as it worked for me. read more...

mail this link | permapage | score:9919 | -falko, December 7, 2009

Tutorial: Build an Ubuntu 9.10 server

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This tutorial shows how to set up an Ubuntu Karmic Koala (Ubuntu 9.10) server that offers all services needed by ISPs and hosters: Apache web server (SSL-capable), Postfix mail server with SMTP-AUTH and TLS, BIND DNS server, Proftpd FTP server, MySQL server, Courier POP3/IMAP, Quota, Firewall, etc. In the end you should have a system that works reliably, and if you like you can install the free webhosting control panel ISPConfig 2 (i.e., ISPConfig runs on it out of the box). read more...

permapage | score:9916 | -falko, November 9, 2009

Hard Drive Partitioning with FDisk

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A concise explantion of partitioning a hard disk using the Linux fdisk utility...

Hard disks can be divided into one or more logical disks called partitions. The partition info is stored in the partition table which is present in the first 512 bytes of the disk.

By default, a hard drive can be divided into 4 partitions but you can have much larger number of logical partitions by dividing one of the primary partition. And only one of the partition can be sub-divided into logical partitions.

System monitoring with munin and monit

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In this article I will describe how you can monitor your Debian Lenny server with munin and monit. munin produces nifty little graphics about nearly every aspect of your server (load average, memory usage, CPU usage, MySQL throughput, eth0 traffic, etc.) without much configuration, whereas monit checks the availability of services like Apache, MySQL, Postfix and takes the appropriate action such as a restart if it finds a service is not behaving as expected. The combination of the two gives you full monitoring: graphics that lets you recognize current or upcoming problems (like "We need a bigger server soon, our load average is increasing rapidly."), and a watchdog that ensures the availability of the monitored services. read more...

mail this link | permapage | score:9903 | -falko, March 1, 2010

Virtual Hosting with Proftpd and MySQL on Ubuntu 9.10

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This document describes how to install a Proftpd server that uses virtual users from a MySQL database instead of real system users. This is much more performant and allows to have thousands of ftp users on a single machine. In addition to that I will show the use of quota with this setup. read more...

permapage | score:9898 | -falko, February 27, 2010

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